Effects of rumen-protected betaine supplementation on meat quality and the composition of fatty and amino acids in growing lambs

Rumen-protected betaine (RPB) can enhance betaine absorption in the small intestine of ruminants, while betaine can alter fat distribution and has the potential to affect the meat quality of livestock. Hence, we hypothesized that RPB might also affect the meat quality of lambs. Sixty male Hu sheep of similar weight (30.47 ± 2.04 kg) were selected and randomly subjected to five different treatments. The sheep were fed a control diet (control treatment, CTL); 1.1 g/day unprotected-betaine supplemented diet (UPB); or doses of 1.1 g/day (low RPB treatment; L-PB), 2.2 g/day (middle RPB treatment; M-PB) or 3.3 g/day (high RPB treatment; H-PB) RPB-supplemented diet for 70 days. Slaughter performance, meat quality, fatty acid and amino acid content in the longissimus dorsi (LD) muscle, shoulder muscle (SM) and gluteus muscle (GM) were measured. Compared with CTL, betaine (including UPB and RPB) supplementation increased the average daily weight gain (ADG) (P < 0.05) and average daily feed intake (P < 0.01) of lambs. Rumen-protected betaine increased ADG (P < 0.05) compared with UPB. With increasing RPB doses, the eye muscle area of the lambs linearly increased (P < 0.05). Compared with CTL, betaine supplementation decreased water loss (P < 0.05) in SM and increased pH₂₄ in the SM (P < 0.05) and GM (P < 0.05). Compared with UPB, RPB decreased water loss in the GM (P < 0.01), decreased shear force (P < 0.05) in the LD and SM and increased the pH of the meat 24 h after slaughter (pH₂₄). With increasing RPB doses, the shear force and b* value in the LD linearly decreased (P < 0.05), and the pH₂₄ of the meat quadratically increased (P < 0.05). Compared with CTL, betaine supplementation increased the polyunsaturated fatty acid in the GM (P < 0.05). Compared with UPB, RPB supplementation decreased the saturated fatty acid (SFA) content in the LD (P < 0.05) and increased the unsaturated fatty acids (UFA), mono-unsaturated fatty acids and UFA/SFA ratio in the LD (P < 0.05). Compared with CTL, the content of histidine in the LD increased with betaine supplementation. Compared with UPB, RPB supplementation increased the content of total free amino acids and flavor amino acids in the LD of lambs (P < 0.05). With increasing RPB, the isoleucine and phenylalanine contents in the LD linearly increased (P < 0.05). Overall, the data collected indicated that the meat quality of lambs (especially in the LD) improved as a result of betaine supplementation, and RPB showed better effects than those of UPB.     

Comparison of muscle fatty acid composition and lipid stability in lambs stall-fed or pasture-fed alfalfa with or without sainfoin pellet supplementation

Currently, consumers are increasingly interested in obtaining high-quality and healthy lamb meat. Compared to grain-based diets, dietary forage legumes such as alfalfa and condensed tannin (CT)-rich sainfoin increase the levels of polyunsaturated fatty acids (PUFAs) that are beneficial for health in lamb meat thanks to their high content in PUFA and/or their impact on ruminal biohydrogenation. However, they can therefore adversely affect its oxidative stability. Thus, the impact of dietary forage legumes on lamb longissimus thoracis (LT) muscle FA composition and their stability to peroxidation was studied in 36 Romane lambs grazing alfalfa (AF; n = 12) or alfalfa plus daily supplementation with CT-rich sainfoin pellets (AS; n = 12; 15 g DM/kg BW, 42 g CT/kg DM) or stall-fed concentrate and grass hay indoors (SI; n = 12). Lambs were slaughtered at a mean age of 162 ± 8.0 days after an average experimental period of 101 ± 8.1 days. Forage legumes-grazing lambs outperformed SI lambs in LT nutritional quality, with more conjugated linoleic acids and n-3 PUFAs, especially 18:3n-3, eicosapentaenoic and docosahexaenoic acids (P < 0.001), and thus lower n-6 PUFA/n-3 PUFA and 18:2 n-6/18:3 n-3 ratios (P < 0.001). Peroxidizability index was higher (P < 0.001) in LT muscle of forage legumes-grazing lambs. Concurrently, two endogenous antioxidant enzyme activities, superoxide dismutase and glutathione peroxidase, were, respectively, similar and lower (P < 0.001) for forage legumes-grazing compared with SI lambs. A lower vitamin E level in SI lambs compared with forage legumes-grazing lambs (1.0 v. 3.8 mg/g, P < 0.001) could explain that malondialdehyde content, a marker of lipid oxidation intensity, was 0.63 µg/g in SI after 8 days in aerobic packaging conditions, whereas it remaining steady at 0.16 µg/g in forage legumes-grazing lambs. Dietary forage alfalfa thus improved FA composition of lamb LT muscle and their stability to oxidation when compared to SI lambs. However, supplementation of alfalfa-grazing lambs with CT-rich sainfoin pellets did not affect the nutritional quality of LT muscle FAs.     

Is a short concentrate-finishing period in lambs raised on alfalfa pasture effective at reducing fat indoles contents and lightening meat colour?

Pasture-feeding in lambs has been associated with dark-coloured meat and high meat contents of volatile indoles (skatole and indole), which may be responsible for sensory defects. The risk of off-flavours is even higher when lambs graze alfalfa, because it is particularly rich in rapidly degradable proteins. Here, we investigated whether a short concentrate stall-finishing period in lambs that previously grazed alfalfa influences meat sensory quality traits. We compared three feeding treatments, using three groups of 10 male Romane lambs: grazing alfalfa (A), stall-feeding with concentrate and straw (S), and stall-finishing with concentrate and straw for 21 days after previously grazing alfalfa (AS). During stall-feeding, the concentrate was given at a level adjusted to achieve a similar growth pattern in all treatment groups, and the length of the trough was sufficient for all lambs to have access to the feeds at the same time. Lamb live weight and age at slaughter, and carcass conformation and fatness were similar for all treatment groups. Perirenal fat skatole content was lower in AS and S lambs than in A lambs (P < 0.001 and P < 0.05, respectively), and not significantly different between AS and S lambs. Perirenal fat indole and dorsal fat skatole concentrations were lower in AS lambs than in A lambs (P < 0.05 and P < 0.005, respectively), the other pairwise comparisons being not significant. There was no treatment effect on dorsal fat indole content. Longissimus et lumborum muscle colour coordinates differed between pasture-fed and stall-fed lambs, with a lower lightness (P < 0.005) and greater redness and hue angle (P < 0.001 and P < 0.01, respectively) in pasture-fed lambs, but muscle colour coordinates did not differ between A and AS lambs. A 21-d concentrate-based stall-finishing period in lambs previously raised on alfalfa pasture therefore markedly reduced fat indoles concentrations compared to lambs grazed on alfalfa until slaughter but did not change meat colour.     

Volatiles in raw and cooked meat from lambs fed olive cake and linseed

This study was conducted to determine the effects of feeding olive cake and linseed to lambs on the volatile organic compounds (VOCs) in raw and cooked meat. Four groups of eight male Appenninica lambs each were fed: conventional cereal-based concentrates (diet C), concentrates containing 20% on a dry matter (DM) basis of rolled linseed (diet L), concentrates containing 35% DM of stoned olive cake (diet OC), or concentrates containing both rolled linseed (10% DM) and stoned olive cake (17% DM; diet OCL). The longissimus dorsi muscle of each lamb was sampled at slaughter and was subjected to VOC profiling through the use of SPME-GC-MS. In the raw meat, the concentration of 3-methylpentanoic acid was higher in treatment C as compared with treatments L, OC and OCL (P<0.01). Moreover the level of nonanoic acid was greater in treatments C and OC than in treatment L (P<0.05). With respect to alcohols, in raw meat the amount of 2-phenoxyethanol in treatment OCL was lower than in treatments C (P<0.01) and OC (P<0.05), while in cooked meat the amount of 1-pentanol was higher in treatment C than in treatment OC (P<0.05). Apart from these compounds, none of the lipid oxidation-derived volatiles was significantly affected by the dietary treatment. Therefore, the results suggest that the replacement of cereal concentrates with linseed and/or olive cake did not cause appreciable changes in the production of volatile organic compounds in lamb meat.     

Dietary supplementation of plant bioactive-enriched aniseed straw and eucalyptus leaves modulates tissue fatty acid profile and nuggets quality of lambs

Utilization of low-input feed resources rich in plant bioactive compounds is a promising strategy for modulating the fatty acid profile in ruminant products. They manipulate microbes involved in rumen biohydrogenation and increase the accumulation of desirable fatty acids at the tissue level. Therefore, the present study was undertaken to assess the effect of dietary supplementation of aniseed straw and eucalyptus leaves on growth performance, carcass traits and fatty acid profile of finisher lambs. Thirty-six Malpura hogget were divided into three treatment groups of 12 each, reared individually in pen (1.6 m × 1.1 m) and fed ad libitum complete feed blocks made up of 55 parts concentrate, 5 parts molasses and 40 parts roughage. Roughage in control (Con) was 20 parts each of ardu (Ailanthus excelsa) leaves and oat (Avena sativa) straw. In test diets, that is, Con-as and Con-el, 10% aniseed (Pimpinella anisum) straw and Eucalyptus rudis leaves, respectively, were added by replacing 5% each of oat straw and eucalyptus leaves. The lambs were weighed weekly; and at the end of 3 months of feeding trial, the lambs were slaughtered to study the carcass traits, composition and product evaluation. Average daily gain (ADG) and DM intake (DMI) was higher (P < 0.05) in Con-as compared to Con and Con-el, while ADG and feed conversion ratio decreased (P < 0.05) by 29.4% and 36.4%, respectively, in Con-el compared to Con. Carcass traits showed lower (P < 0.05) loin eye area and chilling loss in the Con-el group compared to the Con-as and Con, and the total carcass fat compared to Con-as. However, the keeping quality of meat improved in both Con-as and Con-el which was reflected by lower (P < 0.05) thiobarbituric acid-reactive substances values. Nuggets prepared from Con and Con-as meat had superior (P < 0.05) sensory attributes with an overall palatability. Fatty acid profile of longissimus thoracis muscle showed lower (P < 0.05) atherogenic and thrombogenic indices in Con-as and higher (P < 0.05) in Con-el group. Moreover, in Con-as group, the proportion of C16:0 was lower (P < 0.05) and C18:3n-3 was higher (P < 0.05), but no effect was observed on the amount of conjugated linoleic acid (CLA; C18:2 c9t11). In case of adipose tissue, the content of CLA was higher (P < 0.05), and the ratio of n-6:n-3 was more nearer to desirable levels in Con-as group. Therefore, it can be concluded that aniseed straw is a promising feed supplement compared to eucalyptus leaves for improving meat quality and fatty acid profile in lambs.     

Alterations of the fatty acid composition and lipid metabolome of breast muscle in chickens exposed to dietary mixed edible oils

The fatty acid composition of chicken’s meat is largely influenced by dietary lipids, which are often used as supplements to increase dietary caloric density. The underlying key metabolites and pathways influenced by dietary oils remain poorly known in chickens. The objective of this study was to explore the underlying metabolic mechanisms of how diets supplemented with mixed or a single oil with distinct fatty acid composition influence the fatty acid profile in breast muscle of Qingyuan chickens. Birds were fed a corn-soybean meal diet supplemented with either soybean oil (control, CON) or equal amounts of mixed edible oils (MEO; soybean oil : lard : fish oil : coconut oil = 1 : 1 : 0.5 : 0.5) from 1 to 120 days of age. Growth performance and fatty acid composition of muscle lipids were analysed. LC-MS was applied to investigate the effects of CON v. MEO diets on lipid-related metabolites in the muscle of chickens at day 120. Compared with the CON diet, chickens fed the MEO diet had a lower feed conversion ratio (P < 0.05), higher proportions of lauric acid (C12:0), myristic acid (C14:0), palmitoleic acid (C16:1n-7), oleic acid (C18:1n-9), EPA (C20:5n-3) and DHA (C22:6n-3), and a lower linoleic acid (C18:2n-6) content in breast muscle (P < 0.05). Muscle metabolome profiling showed that the most differentially abundant metabolites are phospholipids, including phosphatidylcholines (PC) and phosphatidylethanolamines (PE), which enriched the glycerophospholipid metabolism (P < 0.05). These key differentially abundant metabolites – PC (14:0/20:4), PC (18:1/14:1), PC (18:0/14:1), PC (18:0/18:4), PC (20:0/18:4), PE (22:0/P-16:0), PE (24:0/20:5), PE (22:2/P-18:1), PE (24:0/18:4) – were closely associated with the contents of C12:0, C14:0, DHA and C18:2n-6 in muscle lipids (P < 0.05). The content of glutathione metabolite was higher with MEO than CON diet (P < 0.05). Based on these results, it can be concluded that the diet supplemented with MEO reduced the feed conversion ratio, enriched the content of n-3 fatty acids and modified the related metabolites (including PC, PE and glutathione) in breast muscle of chickens.     

Effects of grain type and conditioning temperature during pelleting on growth performance,ruminal fermentation,meat quality and blood metabolites of fattening lambs

Ruminants can tolerate moderate concentrations of dietary tannin, making it feasible to replace corn with sorghum in ruminant diets; however, conditioning temperature of pelleted total mixed ration (PTMR) greatly affects nutrient digestibility. The objective was to determine effects of grain type and conditioning temperature during pelleting on growth performance, ruminal fermentation, meat quality and blood metabolites of fattening lambs. This was a 2 × 3 factorial study, with corn and sorghum and three conditioning temperatures (65, 75 and 85 °C) in a randomized complete design, with 36 lambs (120 ± 10.2 d and 24.9 ± 3.3 kg) grouped by weight and randomly allocated. The resulting six PTMRs were referred to as 65-S, 75-S and 85-S for sorghum-based diets, and 65-C, 75-C and 85-C for corn-based diets, for low, medium and high pelleting temperatures, respectively. There was no grain type × conditioning temperature (Grain × Temp) interaction on growth performance and apparent nutrient digestibility. Furthermore, grain type did not affect DM intake (DMI), average daily gain (ADG) or feed conversion ratio (FCR) of fattening lambs. Pelleting at 75 °C improved ADG (P < 0.03) and FCR (P < 0.02) of fattening lambs compared to other temperatures. There was a Grain × Temp interaction (P < 0.01) on ruminal pH (lowest in lambs fed 75-S). There tended (P = 0.07) to be a Grain × Temp interaction for total volatile fatty acid (VFA), and there were Grain × Temp interactions for molar proportions of acetate (P < 0.04), butyrate (P < 0.03) and branch-chained VFA (P < 0.01). Lambs fed sorghum-based PTMR had greater molar proportion of propionate (P < 0.03) and lower acetate to propionate ratio (A:P, P < 0.04). Lambs fed sorghum-based PTMR had higher plasma concentrations of urea nitrogen (N) (P < 0.03), glucose (P < 0.01) and alkaline phosphatase (P < 0.05), whereas other blood metabolites were not affected by treatments. There were Grain × Temp (P < 0.03) interactions for color coordinates of longissimus and mid-gluteal muscle. Lambs fed sorghum-based PTMR had lower (P < 0.01) dressing percentage and meat quality than those fed corn-based PTMR. We concluded that sorghum can replace corn in lamb diets without compromising growth performance and feed efficiency; furthermore, feeding sorghum vs corn improved rumen fermentation, with reduced A:P ratio and enhanced N and glucose utilization. Finally, pelleting at 75 °C increased feeding value of either sorghum- or corn-based PTMR for fattening lambs.     

Nitrogen partitioning and isotopic discrimination are affected by age and dietary protein content in growing lambs

It is difficult to separate an age-dependent fall in nitrogen use efficiency (NUE; N balance/N intake) in growing ruminants from a progressively decrease in animal protein requirements over time. This study examined the effect of dietary protein content on N partitioning, digestibility and N isotopic discrimination between the animal and its diet (Δ¹⁵N_animal-diet) evaluated at two different fattening periods (early v. late). Twenty-four male Romane lambs (age: 19 ± 4.0 days; BW: 8.3 ± 1.39 kg) were equally allocated to three dietary CP treatments (15%, 17% and 20% CP on a DM basis). Lambs were reared with their mothers until weaning, thereafter housed in individual pens until slaughter (45 kg BW). During the post-weaning period, lambs were allocated twice (early fattening (30 days post-weaning) and late fattening (60 days post-weaning)) to metabolic cages for digestibility and N balance study. When diet CP content increased, the average daily gain of lambs increased (P < 0.05) while the age at slaughter decreased (P = 0.01), but no effect was observed on feed efficiency (P > 0.10). Diet CP content had limited effect on lamb carcass traits. Higher fibre digestibility was observed at the early v. late fattening period (P < 0.001). The N intake and the urinary N excretion increased when diet CP content increased (P < 0.001) and when shifting from early to late fattening period (P < 0.001). Faecal N excretion (P = 0.14) and N balance (P > 0.10) were not affected by diet CP content. Nitrogen digestibility increased (P < 0.001) as the diet CP content increased and on average it was greater at late v. early fattening period (P = 0.02). The NUE decreased (P = 0.001) as the diet CP content increased and as the lamb became older (P < 0.001). However, the age-dependent fall in NUE observed was lower at high v. low dietary CP content (CP × age interaction; P = 0.04). The Δ¹⁵N_animal-diet was positively correlated (P < 0.05) with N intake (r = 0.59), excretion of faecal N (r = 0.41), urinary N (r = 0.69) and total manure N (r = 0.64), while negatively correlated with NUE (r = −0.57). Overall, the experiment showed NUE was lower in older lambs and when lambs were fed high diet CP content, and that Δ¹⁵N_animal-diet was a useful indicator not only for NUE but also for urinary N excretion, which is a major environmental pollution factor on farm.     

A comparative study of four rumen buffering agents on productive performance,rumen fermentation and meat quality in growing lambs fed a total mixed ration

Controlling rumen fermentation using buffering agents could contribute to enhancing ruminant productivity and performance. This study was realized to investigate the effect of dietary supplementation of AcidBuf, sodium bicarbonate, calseapowder and WMC seaweed (Utva Lactuca extra) on the animal performance, volatile fatty acids, rumen pH, rumen histology and carcass characteristics of growing male Awassi lambs. A total of 60 lambs was divided into five groups. One group served as a control and fed only on a concentrate diet without any buffering, whereas the other four groups were fed the concentrate diet supplemented with 0.4% AcidBuf (Buf1), 0.4% AcidBuf plus sodium bicarbonate, 50 : 50 (Buf2), 0.4% calseapowder (Buf3) or 0.4% WMC Seaweed (Buf4) for 98 days. The feed conversion ratio was (P<0.05) improved in Buf2 compared to the control and other treatment groups. The propionic acid decreased, whereas butyric acid was increased in the treatment groups (P<0.05) compared to the control. The pH of the rumen fluid and the length of submucosa were (P<0.05) higher in Buf4 and Buf1, respectively, compared to the control. Hot and cold carcass weights were (P<0.05) higher in Buf4 compared to Buf1. Lean meat percentage and rib eye area were (P<0.05) higher in Buf4; while the fat percentage was (P<0.05) lower in Buf2 and Buf4 groups compared to the control. The lightness and yellowness of meat were (P<0.05) higher in Buf1 and Buf4 compared to the control. The meat pH was (P<0.05) higher in Buf3 and Buf4 compared to Buf2 (at 1 h) and control (at 24 h). The visceral depot fat (%) was reduced with Buf3 and Buf4 compared to the control. The results indicated that dietary supplementation of different buffering agents improved feed efficiency, rumen pH, carcass characteristics and decreased the body fat in growing Awassi lambs.     

Meat eating and nutritional quality of lambs sired by high and low muscle density rams

Intramuscular fat (IMF) content affects eating and nutritional quality of lamb meat. Muscle density measured by computer tomography is an in vivo proxy measure of IMF content that affects eating and nutritional quality of lamb meat. Lambs sired by high muscle density (HMD) or low muscle density (LMD) rams, selected for slaughter on commercial criteria were measured for meat quality and nutritional traits. A restricted maximum likelihood model was used to compare lamb traits. Additionally, regression analysis of sire estimated breeding value (EBV) for muscle density was performed for each meat quality trait. Muscle density EBV had a negative regression with IMF content (P < 0.001). For each unit increase in muscle density EBV, there was a significant decrease in loin (− 1.69 mg/100 g fresh weight) and topside IMF (− 0.03 mg/100 g fresh weight). Muscle density EBV had a negative regression with grouped saturated and monounsaturated fatty acids concentration (and monounsaturated proportion P < 0.001). Muscle density EBV had a negative regression with loin sensory traits tenderness, juiciness and overall liking and many novel tenderness sensory traits measured (P < 0.05). Selecting for LMD EBV increased IMF content and favourable meat eating quality traits. In contrast, sire muscle density EBV had a positive regression with loin polyunsaturated:saturated fat ratio and grouped polyunsaturated proportion traits (including total polyunsaturated proportion, total omega-6 (n-6) and total omega-3 (n-3) fatty acids (P < 0.001). This is explained by the fact that as sire muscle density EBV increases, polyunsaturated fatty acid proportion increases and the proportion of saturated and monounsaturated fatty acid content decreases. Muscle density EBV had a positive regression with shear force and the novel toughness sensory traits (P < 0.05). Selection for HMD EBV's increased shear force and toughness traits, which is unfavourable for the consumer. Low muscle density sired meat had higher meat colour traits chroma/saturation (+ 0.64, SD 2.30, P = 0.012), redness (+ 0.52, SD 1.91, P = 0.012) and yellowness (+ 0.31, SD 1.49, P = 0.08) compared to HMD sired meat. Selection for LMD could be used within a breeding programme to increase IMF content and enhance both meat colour and improve eating quality parameters.     

Effect of different dietary tannin extracts on lamb growth performances and meat oxidative stability: comparison between mimosa,chestnut and tara

Little information is available on the effects of different sources of tannins on ruminant product quality. Nowadays several tannin-rich extracts, produced from different plants, are available and contain tannins belonging to different chemical groups, but most of these have not been used so far as feed supplements. The present study aimed at comparing the effects of feeding three tannin extracts (one containing condensed tannins and two containing hydrolysable tannins) to lambs on growth performances and meat oxidative stability. Comisana male lambs were divided into four groups (n=9 each) and were fed for 75 days: a concentrate-based diet (CON), or CON supplemented with 4% tannin extracts from either mimosa (MI; Acacia mearnsii, De Wild; condensed tannins), chestnut (CH; Castanea sativa, Mill; hydrolysable ellagitannins) or tara (TA; Cesalpinia spinosa, (Molina) Kuntze; hydrolysable gallotannins). Only CH reduced growth rate, final weight, carcass weight and feed intake (P<0.05). Tannins did not affect the concentration of the main fatty acid classes and the peroxidability of the intramuscular fat (P>0.05). The TA diet increased (P<0.001) the concentration of γ-tocopherol in muscle and tended to increase that of α-tocopherol (P=0.058). Oxidative stability of raw and cooked meat, or of meat homogenates incubated with pro-oxidants, was not affected by the extracts. These results, compared with those reported in the literature, highlight that some effects of tannins cannot be easily generalized, but may strictly depend on their specific characteristics and on conditions inherent to the basal diet and the metabolic status of the animals.     

Effects of dietary incorporation of linseed oil with soybean isoflavone on fatty acid profiles and lipid metabolism-related gene expression in breast muscle of chickens

The meat quality of chicken is an important factor affecting the consumer’s health. It was hypothesized that n-3 polyunsaturated fatty acid (n-3 PUFA) could be effectively deposited in chicken, by incorporating antioxidation of soybean isoflavone (SI), which led to improved quality of chicken meat for good health of human beings. Effects of partial or complete dietary substitution of lard (LA) with linseed oil (LO), with or without SI on growth performance, biochemical indicators, meat quality, fatty acid profiles, lipid-related health indicators and gene expression of breast muscle were examined in chickens. A total of 900 males were fed a corn–soybean meal diet supplemented with 4% LA, 2% LA + 2% LO and 4% LO and the latter two including 30 mg SI/kg (2% LA + 2% LO + SI and 4% LO + SI) from 29 to 66 days of age; each of the five dietary treatments included six replicates of 30 birds. Compared with the 4% LA diet, dietary 4% LO significantly increased the feed efficiency and had no negative effect on objective indices related to meat quality; LO significantly decreased plasma triglycerides and total cholesterol (TCH); abdominal fat percentage was significantly decreased in birds fed the 4% LO and 4% LO + SI diets. Chickens with LO diets resulted in higher contents of α-linolenic acid (C18:3n-3), EPA (C20:5n-3) and total n-3 PUFA, together with a lower content of palmitic acid (C16:0), lignoceric acid (C24:0), saturated fatty acids and n-6:n-3 ratio in breast muscle compared to 4% LA diet (P < 0.05); they also significantly decreased atherogenic index, thrombogenic index and increased the hypocholesterolemic to hypercholesterolemic ratio. Adding SI to the LO diets enhanced the contents of EPA and DHA (C22:6n-3), plasma total superoxide dismutase, reduced glutathione (GSH)/oxidized glutathione and muscle GSH content, while decreased plasma total triglyceride and TCH and malondialdehyde content in plasma and breast muscle compared to its absence (P < 0.05). Expression in breast muscle of fatty acid desaturase 1 (FADS1), FADS2, elongase 2 (ELOVL2) and ELOVL5 genes were significantly higher with the LO diets including SI than with the 4% LA diet. Significant interactions existed between LO level and inclusion of SI on EPA and TCH contents. These findings indicate that diet supplemented with LO combined with SI is an effective alternative when optimizing the nutritional value of chicken meat for human consumers.     

Influence of level of inclusion of Azolla leaf meal on growth performance,meat quality and skeletal muscle p70S6 kinase α abundance in broiler chickens

The interest in biodiesel production from oil-bearing seeds rather than soybean necessitates the scientific validation of other good quality protein sources that could substitute soybean meal in animal diets, particularly, broiler chickens where soybean meal constitutes a large portion of their diet. Therefore, the present study was conducted to investigate the effect of sun-dried Azolla leaf meal (ALM) as an unconventional dietary protein source in broiler chicken diet on growth performance, meat quality, skeletal muscle cell growth and protein synthesis through regulation of ribosomal protein S6 kinase (p70S6 kinase α). A total of 120 male Ross 308 broiler chicks were randomly allocated to three dietary treatments. Each treatment had four cages (i.e. replicates) with 10 birds/cage. The control group was fed with a corn–soy-based diet, the AZ5 group was supplemented with 5% ALM and the AZ10 group was supplemented with 10% ALM for 37 days. A 5-day trial was also conducted to measure the apparent nutrient digestibility. Growth performance parameters were measured weekly. At the end of the experiment, 12 birds from each group (3/cage) were euthanized and used for samplings. Inclusion of ALM tended to improve BW gain (P = 0.06) and increased feed intake (P < 0.01). Additionally, ALM decreased the percentage of breast meat cooking loss linearly (P < 0.01). In addition, ALM at a dose of 5% increased the production of propionate in the cecum (P = 0.01). Activation of breast muscle p70S6 kinase was higher when ALM was included in a dose-dependent manner (P < 0.01). The inclusion of ALM increased breast meat redness (P < 0.01); however, the lightness was within the normal range in all groups. Findings from our study suggest that ALM could be included in a broiler chicken diet up to 5% without any major negative effect on meat quality or performance, and it regulates muscle protein synthesis through activation of mammalian target of rapamycin/6S kinase signaling.     

Effects of inulin and di-d-fructose dianhydride-enriched caramels on intestinal microbiota composition and performance of broiler chickens

In vitro and in vivo experiments were designed to evaluate the effectiveness of laboratory-made di-d-fructose dianhydride (DFA)-enriched caramels. The DFA-enriched caramels were obtained from d-fructose (FC), d-fructose and sucrose (FSC), or d-fructose and β-cyclodextrin (FCDC). In the in vitro experiment, raftilose and all caramels increased (P<0.05) l-lactate concentration and decreased (P<0.05) pH. Total short-chain fatty acid concentration was higher (P<0.05) than controls in tubes containing raftilose, FSC, FCDC and commercial sucrose caramel (CSC). Raftilose, and all caramels tested except FSC and FC (1%), increased (P<0.01) lactobacilli log₁₀ number of copies compared with the non-additive control. FSC, FCDC and CSC increased (P<0.01) the bifidobacteria number of copies as compared with controls. All additives, except FCDC, decreased (P<0.01) Clostridium coccoides/Eubacterium rectale log number of copies. Compared with controls, raftilose, FC and CSC led to lower (P<0.01) Escherichia–Shigella and enterobacteria. For the in vivo experiment, a total of 144 male 1-day-old broiler chickens of the Cobb strain were randomly assigned to one of the three dietary treatments for 21 days. Dietary treatments were control (commercial diet with no additive), inulin (20 g inulin/kg diet) and FC (20 g FC/kg diet). Final BW of birds fed FC diet was higher (P<0.01) than controls or inulin-fed birds, although feed: gain values were not different. Feed intake of chickens fed FC was higher (P<0.01) than that of inulin-fed birds but not statistically different from controls. Crop pH values were lower (P<0.01) in birds fed FC diet as compared with control diet, with inulin-fed chickens showing values not different from control- or FC-fed birds. Lower (P<0.05) lactobacilli number of copies was determined in the crop, ileum and caeca of birds fed the inulin diet compared with the control diet. Inulin supplementation also resulted in lower (P<0.05) C. coccoides/E. rectale, bacteroides and total bacteria in caecal contents. Addition of FC to broiler diets gave place to lower (P<0.05) enterobacteria and Escherichia–Shigella in crop and caecal contents compared with controls. The bacteroides number of copies increased (P<0.05) as compared with controls in the ileum, but decreased (P<0.05) in the caeca of chickens fed the FC diet. Energy, ADF, NDF and non-starch polysaccharides faecal digestibilities were greater (P<0.05) than controls in chickens fed diets containing inulin or FC. Fat digestibility was higher (P<0.05) in FC-fed birds compared with controls or inulin-fed chickens. In conclusion, DFA-enriched caramels tested here, particularly FC, may represent a type of new additives useful in poultry production.     

Effect of raw and fermented grape seed on growth performance,antioxidant capacity,and cecal microflora in broiler chickens

Grape seed (GS) is a by-product of the fruit juice and wine industry with the potential to be an alternative to synthetic antioxidants due to its antioxidant activity. Agro-industrial residues can be converted to more effective products by solid-state fermentation. The objective of the study was to investigate the effects of GS and fermented grape seed (FGS) on the growth performance, antioxidant capacity, and cecal microflora in broiler chickens. A total of 128 female broilers were randomly allocated into four treatment groups, each consisting of four replicates of eight birds. Throughout the 42-day feeding period, the birds were fed with soybean-corn based diet (CON), 0.15 g/kg synthetic antioxidant (butylated hydroxyanisole) supplemented diet (AO), 5 g/kg GS supplemented diet (GS), and 5 g/kg FGS supplemented diet (FGS). Dietary GS, FGS, and AO supplementation increased the BW (P < 0.05) and average daily weight gain (ADG, P < 0.05) compared with the CON group in the overall period of 42 days. Dietary FGS also increased the ADG (P < 0.05) in the period of 22–42 days compared with the control group. The pH of the breast meat of the chickens fed GS was higher (P < 0.01) than CON and FGS groups. Dietary FGS and AO decreased the b* value (P < 0.01) of breast meat compared with the CON group. Grape seed had the highest serum glutathione peroxidase (P < 0.05) and catalase (CAT, P < 0.01) levels among the treatment groups. The FGS also increased serum CAT level (P < 0.01) compared with the AO group. Moreover, dietary FGS supplementation increased Lactobacillus spp. (P < 0.05) in the cecum compared with the other treatment groups and decreased Staphylococcus aureus (P < 0.05) compared with the CON and AO groups. The present findings indicate that GS and FGS can be used in broiler diets as alternatives to synthetic antioxidants.     

Effects of physical forms of starter feed on growth,nutrient digestibility,gastrointestinal enzyme activity,and morphology of pre- and post-weaning lambs

The physical form of starter feed may affect the gastrointestinal development and the performance of ruminant. However, little information is available on how changes in the physical forms of starter feed influence the performance of lambs, especially during the pre- and post-weaning periods. The aim of this study was to investigate the effects of different physical forms of starter feeds on growth performance, nutrient digestibility, gastrointestinal enzyme activity, and morphology of pre- and post-weaning lambs. Twenty-four 8-day-old male Hu lamb (5.04 ± 0.75 kg BW) were randomly assigned to one of two dietary treatments: 1) a pelleted starter (PS) feed and 2) a textured starter (TS) feed, which included coarse mashed steam-flaked corn. From eight to thirty-five days of age (pre-weaning), the lambs were bottle-fed milk replacer (MR) at 2% of BW measured on day 8. All lambs were weaned at day 35 when feeding of MR was stopped. Six lambs for each treatment were euthanized at 21 or 42 days of age for sampling. The following results are obtained by variance analysis: TS lambs had a greater (P < 0.05) final BW, higher apparent digestibility of starch and ether extract, activities of α-amylase pre- or post-weaning, and higher (P < 0.05) average dry matter intake and lipase post-weaning in small intestine contents and had a trend of significantly higher average daily gain post-weaning (P = 0.07). Rumen development analysis of TS lambs showed a significantly higher (P < 0.05) relative weight of rumen post-weaning, greater papillae length, increased circular and layered muscle, increased sectional area pre- and post-weaning, and increased rumen papillae width post-weaning. Textured starter treatment increased the villus height and villus width (except jejunum pre-weaning) of the whole small intestine and villus height to crypt depth ratio of jejunum and ileum during the whole period and tended to increase the relative weight of the rumen pre-weaning (P = 0.07). The results indicated that TS feeding is more beneficial to lambs over the weaning transition than PS in promoting gastrointestinal development, intestinal enzyme activities, nutrient digestibility, and growth performance. The findings provide new insights into the selection of physical forms of starter feeds in lamb production. Further research with more animals and female lambs is needed to obtain a more complete conclusion.     

Grape pomace improves performance,antioxidant status,fecal microbiota and meat quality of piglets

In the present study, grape pomace (GP) was used as feed additive in the diet of weaned piglets in order to develop innovative feedstuffs and to investigate their potential beneficial effects on welfare, productivity and meat quality. For examining the antioxidant capacity of the experimental feeds, 24 piglets of 20 days old were assigned to two experimental groups receiving standard or experimental diet for 30 days. Blood and tissues collections were performed at four different time-points, 2, 20, 35 and 50 days post birth. The collected tissues were brain, heart, kidney, liver, lung, quadriceps muscle, pancreas, spleen and stomach. The following oxidative stress markers were assessed: reduced glutathione (GSH), catalase activity, total antioxidant capacity (TAC), thiobarbituric acid reactive substances (TBARS), protein carbonyls (CARB) and H₂O₂ decomposition activity. The effect on bacterial growth was assessed by examining microbial populations in piglets’ fecal microbiota. Furthermore, the average daily gain (ADG) was calculated and the fatty acid profile of quadriceps muscle was assessed. The results showed that piglets fed with the diet supplemented with GP, had significantly increased antioxidants mechanisms in almost all the tissues as shown by increases in GSH, H₂O₂ decomposition activity and TAC compared with control group. Piglets fed with the experimental diet exhibited decreased oxidative stress-induced damage to lipids and proteins as shown by decreases in TBARS and CARB in GP group compared with control. In addition, the experimental diet increased significantly ADG (by 23.65%) (P<0.05) and enhanced the growth of facultative probiotic bacteria (by up to 1.2 log colony forming units (CFU)/g) (P<0.05) and lactic acid bacteria (by up to 2.0 log CFU/g) (P<0.05) in GP group compared with the control group. GP supplementation inhibited the growth of pathogen populations such as Enterobacteriacae (by up to 1.8 log CFU/g) (P<0.05) and Campylobacter jejuni (by up to 1.0 log CFU/g) (P<0.05). Regarding fatty acid composition of meat, GP inclusion in piglets’ diet increased significantly n-3 fatty acids (EPA; C20 : 5n-3, DHA; C22 : 6n-3, α-linolenic acid; C18 : 3n-3) and decreased significantly n-6/n-3 ratio compared with control (P<0.05). The results suggested that dietary GP supplementation may have a beneficial impact on piglets’ welfare and may improve productivity as well as meat quality.     

Effects of soybean isoflavones on the growth performance,intestinal morphology and antioxidative properties in pigs

Soybean meal is rich in soybean isoflavones, which exhibit antioxidant, anti-inflammatory, antiviral and anticancer functions in humans and animals. This study was conducted to investigate the effects of soybean isoflavones on the growth performance, intestinal morphology and antioxidative properties in pigs. A total of 72 weaned piglets (7.45 ± 0.13 kg; 36 males and 36 females) were allocated into three treatments and fed corn-soybean meal (C-SBM), corn-soy protein concentrate (C-SPC) or C-SPC supplemented with equal levels of the isoflavones found in the C-SBM diet (C-SPC + ISF) for a 72-day trial. Each treatment had six replicates and four piglets per replicate, half male and half female. On day 42, one male pig from each replicate was selected and euthanized to collect intestinal samples. The results showed that compared to pigs fed the C-SPC diet, pigs fed the C-SBM and C-SPC + ISF diets had higher BW on day 72 (P < 0.05); pigs fed the C-SBM diet had significantly higher average daily gain (ADG) during days 14 to 28 (P < 0.05), with C-SPC + ISF being intermediate; pigs fed the C-SBM diet tended to have higher ADG during days 42 to 72 (P = 0.063), while pigs fed the C-SPC + ISF diet had significantly higher ADG during days 42 to 72 (P < 0.05). Moreover, compared to pigs fed the C-SPC diet, pigs fed the C-SBM diet tended to have greater villus height (P = 0.092), while pigs fed the C-SPC + ISF diet had significantly greater villus height (P < 0.05); pigs fed the C-SBM and C-SPC + ISF diets had significantly increased villus height-to-crypt depth ratio (P < 0.05). Compared with the C-SPC diet, dietary C-SPC + ISF tended to increase plasma superoxide dismutase activity on days 28 (P = 0.085) and 42 (P = 0.075) and reduce plasma malondialdehyde (MDA) content on day 42 (P = 0.089), as well as significantly decreased jejunal mucosa MDA content on day 42 (P < 0.05). However, no significant difference in the expression of tight junction genes among the three groups was found (P > 0.05). In conclusion, our results suggest that a long-term exposure to soybean isoflavones enhances the growth performance, protects the intestinal morphology and improves the antioxidative properties in pigs.     

Using mixed silages of sweet sorghum and alfalfa in total mixed rations to improve growth performance,nutrient digestibility,carcass traits and meat quality of sheep

Combining sweet sorghum (SS) with alfalfa for ensiling has the potential to make a high-quality silage with relatively a better nutrient balance. However, the existing data are insufficient about how changes in ratios of SS to alfalfa in different silage mixtures affect animal performance and meat quality. Therefore, the objective of this study was to determine the effect of feeding total mixed rations containing mixed silages of SS and alfalfa on growth performance, nutrient digestibility, carcass traits and meat quality of Karakul sheep. Five total mixed rations were formulated with different SS proportions at 100%, 80%, 60%, 40%, and 20% on a fresh weight basis. Thirty 4-month old male Karakul sheep with 25.5 ± 1.4 kg BW were randomly allocated into five treatment groups, each with six lambs for this experiment. The results indicated that the Karakul sheep consuming total mixed rations containing SS-Alfalfa (SS-AF) silage mixtures with a lower proportion of SS tended to increase nutrient digestibility, growth performance, carcass traits, and meat quality. Feeding diets with SS at 40% and 20% inclusion rate showed a significant linear increase in the apparent digestibility of DM, CP and NDF, as well as subcutaneous fat thickness and water holding capacity (P < 0.5). Moreover, reduction in SS inclusion rate in these diets caused significant (P < 0.05) linear and quadratic increases in DM intake, final BW, average daily gain, carcass weight, and the amino acid contents of meat (P < 0.05). Conversely, feeding diet with lower SS inclusion rate led to decrease in feed conversion ratio and shear force significantly (P < 0.05) for these sheep. It appears that 40% inclusion of SS was the optimal rate in making the SS-AF silage mixture for lambs to achieve a superior production performance and high-quality meat products in Karakul sheep. However, further research is needed to investigate the effect of feeding SS-AF silage mixtures alongside contrasting ingredients on rumen function, ruminal microorganisms and digestive enzyme activity of sheep and other ruminant animals.     

Consequences of rearing feeding programme on the performance of rabbit females from 1st to 2nd parturition

To evaluate how rearing programmes could affect resources allocation and reproductive performance of primiparous rabbit females, a total of 118 rabbit females were used to evaluate the effects of five rearing feeding programmes on their performance from 1st to 2nd parturition: CAL, fed ad libitum C diet (11.0 MJ digestible energy (DE), 114 g digestible protein (DP) and 358 g NDF/kg dry matter (DM) until 1st parturition; CR, fed ad libitum with C diet until 12 weeks of age and then C diet restricted (140 g/day) until 1st parturition; F, fed ad libitum with F diet (8.7 MJ DE, 88 g DP and 476 NDF/kg DM) until 1st parturition; FC, fed with F diet ad libitum until 16 weeks of age, and C diet ad libitum until 1st parturition; FCF, fed with F diet ad libitum until 16 weeks of age, then C diet ad libitum until 20 weeks and then F diet ad libitum until 1st parturition. From 1st parturition, C diet was ad libitum offered to all the experimental groups until 2nd parturition. CAL females presented lower feed intake than females of F, FC and FCF groups in the 1^st week of lactation (on av. −16.6%; P<0.05). During 1st lactation, the perirenal fat thickness change in CAL females was not different from 0 (+0.02 mm), while in the other four groups it increased (on av. +0.44 mm; P<0.05). Plasma of females fed with F diet during rearing (F, FC and FCF) had lower non-esterified fatty acids content than those exclusively fed with C diet (–0.088 and –0.072 mmol/l compared to CAL and CR, respectively; P<0.05). FCF litters had higher weight than F litters at day 21 of lactation (+247 g; P<0.05), but FCF litter had significantly lower weight than FC litters at weaning (+170 g; P<0.05). CR females had the shortest average interval between the 1st and 2nd parturition (49 days) and FCF females the longest (+ 9 days compared to CR; P<0.05). At 2nd parturition, liveborn litters of F females were larger and heavier than litters of FCF females (+2.22 kits and +138 g; P<0.05), probably due to the lower mortality at birth of F litters (–16.5 percentage points; P<0.05). In conclusion, rearing females on fibrous diets seems to increase the ability of primiparous rabbit females to obtain resources, especially at the onset of lactation.