Effects of folic acid on growth performance,ruminal fermentation,nutrient digestibility and urinary excretion of purine derivatives in post-weaned dairy calves

This study evaluated the effects of folic acid (FA) supplementation on growth performance, ruminal fermentation, nutrient digestibility and urinary purine derivatives (PD) excretion in dairy calves. Forty-eight Chinese Holstein male dairy calves at 60 ± 3.2 d of age and 89 ± 5.9 kg body weight (mean ± standard error) were assigned to one of four groups in a randomised block design. Calves in control group were fed basal diet, calves in low FA, medium FA and high FA groups with 3.6, 7.2 and 10.8 mg FA per kg basal diet, respectively. The dietary corn silage to concentrate ratio was 50:50 (dry matter [DM] basis). DM intake and average daily gain (ADG) quadratically increased, and feed conversion ratio quadratically decreased with increasing FA supplementation. Ruminal pH linearly decreased, whereas total volatile fatty acids quadratically increased. The unchanged acetate-to-propionate ratio was due to the similar change in acetate and propionate concentration. Ammonia N content quadratically decreased. Digestibility of DM, organic matter, crude protein, ether extract, neutral detergent fibre and acid detergent fibre linearly increased. Activities of carboxymethyl cellulase, cellobiase, xylanase and pectinase linearly increased, but α-amylase and protease quadratically increased. Abundance of Ruminococcus albus, Ruminococcus flavefaciens and Fibrobacter succinogenes linearly increased, but Butyrivibrio fibrisolvens and Prevotella ruminicola quadratically increased. Urinary total PD excretion quadratically increased. The results indicated that FA supplementation increased ADG, ruminal fermentation and nutrient digestibility with promoted ruminal microbial growth and enzyme activity, and the optimum dose was 7.2 mg FA per kg basal diet for calves.     

Untersuchungen zum Einsatz von ammonisierten Strohpellets als alleinige Grundration in der Wiederkäuerfütterung

Because legumes are a very important feed source for ruminants, the aim of this study was to evaluate the ideal inclusion level of hay Arachis pintoi cv. Belmonte in sheep diets by measuring the dry matter intake (DMI), concentration of volatile fatty acids, ammonia–nitrogen concentration, ruminal pH and the in situ degradability of dry matter (DM) and crude protein (CP). In the experiment with four sheep, a 4 × 4 Latin Square design was used with four periods and four treatments (0%, 30%, 60% and 100% Arachis replacing grass hay). Significant interactions were observed between treatments and sampling times for ammonia–nitrogen and acetate, propionate and butyrate concentration and the acetate:propionate ratio. The ruminal pH and total volatile fatty acids concentration were not affected by interaction between treatments and sampling time. The degradation of DM and CP was similar, rising with the increasing content of Arachis, showing a linear effect. The treatment containing 60% of Arachis showed best results, with good levels of daily weight gain and higher ruminal concentrations of volatile fatty acids. The legume showed high levels of CP, high digestibility and appropriate levels of fibre, with excellent standards of degradation and ruminal characteristics. The use of the legume Arachis for ruminants is a promising option of nutrient supply to meet production demands of these animals.     

Effect of High-Dose Nano-selenium and Selenium–Yeast on Feed Digestibility, Rumen Fermentation, and Purine Derivatives in Sheep

The aim of this study was to evaluate the effect of nano-selenium (NS) and yeast?Cselenium (YS) supplementation on feed digestibility, rumen fermentation, and urinary purine derivatives in sheep. Six male ruminally cannulated sheep, average 43.32?±?4.8?kg of BW, were used in a replicated 3?×?3 Latin square experiment. The treatments were control (without NS and YS), NS with 4?g nano-Se (provide 4?mg Se), and YS with 4?g Se-yeast (provide 4?mg Se) per kilogram of diet dry matter (DM), respectively. Experimental periods were 25?days with 15?days of adaptation and 10?days of sampling. Ruminal pH, ammonia N concentration, molar proportion of propionate, and ratio of acetate to propionate were decreased (P?<?0.01), and total ruminal VFA concentration was increased with NS and YS supplementation (P?<?0.01). In situ ruminal neutral detergent fiber (aNDF) degradation of Leymus chinensis (P?<?0.01) and crude protein (CP) of soybean meal (P?<?0.01) were significantly improved by Se supplementation. Digestibilities of DM, organic matter, crude protein, ether extract, aNDF, and ADF in the total tract and urinary excretion of purine derivatives were also affected by feeding Se supplementation diets (P?<?0.01). Ruminal fermentation was improved by feeding NS, and feed conversion efficiency was also increased compared with YS (P?<?0.01). We concluded that nano-Se can be used as a preferentially available selenium source in ruminant nutrition.     

Effects of dietary addition of cellulase and a Saccharomyces cerevisiae fermentation product on nutrient digestibility,rumen fermentation and enteric methane emissions in growing goats

This study was designed to assess the effectiveness of dietary cellulase (243 U/g, derived from Neocallimastix patriciarum) and a Saccharomyces cerevisiae fermentation product (yeast product) on ruminal fermentation characteristics, enteric methane (CH₄) emissions and methanogenic community in growing goats. The experiment was conducted in a 5 × 5 Latin square design using five Xiangdong black wether goats. The treatments included a Control and two levels of cellulase (0.8 g and 1.6 g/kg dry matter intake (DMI), i.e. 194 U/kg and 389 U/kg DMI, respectively) crossed over with two levels (6 g or 12 g/kg DMI) of the yeast product. There were no significant differences regarding feed intake, apparent digestibility of organic matter, neutral detergent fibre and acid detergent fibre among all the treatments. In comparison with the Control, the ruminal ammonia N concentration was decreased (p = 0.001) by cellulase and yeast product addition. The activities of carboxymethylcellulase and xylanase were decreased after cellulase addition. Moreover, dietary cellulase and yeast product addition led to a significant reduction (p < 0.05) of enteric CH₄ emissions although the diversity and copy numbers of methanogens among treatments were not dissimilar. The present results indicate that the combination of cellulase and yeast fermentation product can reduce the production of CH₄ energy and mitigate the enteric CH₄ emissions to a certain degree.     

Intake and digestion by lambs of dwarf elephant grass (Pennisetum purpureum Schum. cv. Mott) hay or hay supplemented with urea and different levels of cracked corn grain

This study was carried out to evaluate intake, digestibility, ruminal fermentation, nitrogen (N) retention and ruminal microbial protein synthesis in lambs fed dwarf elephant grass (Pennisetum purpureum Schum. cv. Mott) hay or hay supplemented with urea and 0, 5, 10 or 15 g/kg of live weight (LW) of cracked corn grain. Ten lambs (mean LW of 28 ± 0.9 kg), housed in metabolic cages, were used in a double 5 × 5 Latin Square experiment. Except fibre intake and digestibility, which was higher, the intake and digestibility of the others feed components, as well as ruminal microbial protein synthesis and N retention were lower in non-supplemented lambs. Corn supplementation increased total dry matter (DM) (P<0.05), organic matter (OM), non-structural carbohydrate (NSC) and energy intake (P<0.01) but decreased total neutral detergent fibre (aNDFom) (P<0.01) intake, as well as OM and aNDFom intake from the hay (P<0.01). Apparent DM, OM and energy digestibility, as well as OM true digestibility (OMTD) increased (P<0.01), and aNDFom digestibility decreased linearly (P<0.01) as corn supplementation increased. Total N intake was not influenced but, apparent and true N digestibility, as well as urinary N excretion decreased (P<0.01), and ruminal microbial N entering the small intestine increased linearly (P<0.01) as corn supplementation increased. However, the efficiency of ruminal microbial protein synthesis was similar for all treatments. Mean ruminal pH values and ammonia N concentrations decreased linearly (P<0.01) with level of corn supplementation. Ammonia N and amino acid, as well as peptide concentrations in ruminal fluid were quadratically related (P<0.01) with the time after feeding. Corn supplementation had a linear additive effect on total dry matter and digestible energy intake, as well as on N retention, but a linear negative effect on hay intake and on fibre digestibility. However, decreased forage digestibility by animals was probably neither related to lower ruminal pH, which values were always higher than 7.0, nor related to ruminal sugar concentrations, which were similar for all treatments.     

Effects of dietary inclusion of Moringa oleifera leaf meal on nutrient digestibility,rumen fermentation,ruminal enzyme activities and growth performance of buffalo calves

This study was conducted to investigate the impact of dietary inclusion of Moringa oleifera leaf meal (MLM) as a substitution for soybean meal on nutrient digestibility, rumen fermentation, rumen enzyme activity, blood metabolites, growth-related hormones, and growth performance of buffalo calves. Thirty buffalo calves eight to nine months of age with an average body weight of approximately 153.7 ± 0.97 kg were randomly distributed through three dietary treatments (ten calves/treatment). MLM inclusion rates were 15% (M15) and 20% (M20), replacing soybean meal by 50 and 75% in the concentrate mixture, respectively. The results indicated that, digestibility of dry matter, organic matter (OM), and crude fiber (CF) increased significantly (p < 0.05) with MLM inclusion, while the digestibility of crude protein (CP) and ether extract (EE) reduced significantly (p < 0.05) with MLM addition. Dietary supplementation with MLM significantly affected (p < 0.001) rumen fermentation by reducing ruminal enzymes, ruminal ammonia-N, total protozoa, and acetate/propionate ratio and increasing acetic, propionic, and butyric acids and total volatile fatty acid concentrations (p < 0.001). Furthermore, dietary inclusion of 15% MLM significantly improved (p < 0.001) final body weight, dry matter intake of feed, daily weight gain, feed conversion efficiency, blood metabolites, and plasma insulin growth factor-I (IGF-I). It can be concluded that MLM is a multi-purpose protein supplement that provides some nutritional and therapeutic advantages when replacing 50% of soybean meal. Dietary supplementation of 15% MLM improved rumen fermentation, growth performance, blood metabolites, plasma IGF-I and mitigated ammonia and methane without any adverse effects in growing buffalo calves.     

Effect of different levels of concentrate on ruminal microorganisms and rumen fermentation in Nellore steers

The aim of this study was to investigate the effect of different dietary levels of concentrate on feed intake, digestibility, ruminal fermentation and microbial population in steers. Eight Nellore steers fitted with ruminal cannulas were used in a double 4 × 4 Latin square design experiment. The dietary treatments consist of four different proportions of concentrate to roughage: 30:70, 40:60, 60:40 and 80:20% in the dry matter, resulting in Diets 30, 40, 60 and 80, respectively. The roughage was corn silage, and the concentrate was composed of corn, soybean meal and urea. Apparent digestibility of organic matter and crude protein showed a linear association with concentrate proportion (p = 0.01), but the increased concentrate levels did not affect the digestibility of fibre. The lowest ruminal pH-values were observed in animals fed with Diet 80, remaining below pH 6.0 from 6 h after feeding, while in the other diets, the ruminal pH was below 6.0 not before 12 h after feeding. After feeding Diet 80, the ammonia concentration in the rumen was significantly the highest. Higher dietary concentrate levels resulted in a linear increase of propionic acid concentrations, a linear reduction of the ratio acetic acid to propionic acid (p < 0.01) and a linear increased synthesis of microbial nitrogen (p < 0.001). The predicted production of methane was lower in diets with greater amounts of concentrate (p = 0.032). The population of methanogens, R. flavefaciens and R. albus decreased with higher concentrate levels, while the population of S. ruminantium increased (p < 0.05). The results indicate that greater amounts of concentrate do not decrease ruminal pH-values as much as expected and inhibit some cellulolytic bacteria without impairing the dry matter intake and fibre digestibility in Nellore steers.     

In vitro studies and short-term feeding trial in lambs to evaluate plantain sheath (Musa sapientum) as a feed for ruminants

Plantain sheath (Musa sapientum) contained 6.4% dry matter and 3.4% crude protein, 31.4% crude fibre, 34.6% cellulose, 15.5% hemicellulose and 6% lignin in dry matter.

Digestibility in vitro studies with fistulated bucks revealed a dry matter disappearance of 53.3% after 24 h incubation. The digestibility of neutral detergent fibre (NDF), acid detergent fibre (ADF) and cellulose after 24 h fermentation was 32.2, 21.5 and 30.3%, respectively. After 48 h fermentation, the dry matter digestibility increased to 63.4%, NDF to 47.0%, ADF to 32.2% and cellulose to 42.3%.

A 45-day feeding trial was conducted with 16 crossbred lambs. Plantain sheath replaced paragrass hay dry matter at 32.6, 54.7 and 76.6% levels. Dried plantain sheath, which contributed 14.1, 25 and 34.5% of total dry matter intake, helped a daily gain of 31.1, 28.9 and 37.8 g when fed mixed with concentrate feed.     

Growth performance and carcass characteristics of Awassi lambs and Shami goat kids fed yeast culture in their finishing diet

Two experiments were completed to examine effects of inclusion of a yeast culture (YC) to a diet based on barley grain and wheat straw on digestibility, growth and meat traits of Awassi lambs and Shami goat kids. Experiment 1 studied effects of YC on apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and N balance in sheep, while experiment 2 studied effects on growth performance and carcass composition of lambs and kids. The same diet was used in both experiments and the YC was added to the diet of treated groups at the level of 12.6 kg YC/tonne of diet. Addition of YC had no effect on apparent digestibility of DM, CP and NDF, but it increased (P<0.05) digestibility of OM and ADF. No differences occurred in N intake, output or retention. Addition of YC did not affect growth rate, or DM intake, in both lambs and kids. YC supplementation to lambs reduced hot carcass weight, cold dressing proportion and total muscle/bone ratio, but increased empty digestive tract weight. There were no changes in back fat thickness, intermuscular fat of the leg muscle, and weights and proportions of carcass cuts. Measures of kids’ carcass characteristics and quality also did not differ. Only cuts of leg and shoulder differed (P<0.05) when calculated as a proportion of the whole carcass cut. Results show that YC supplementation increased digestibility with no effect on growth, feed intake or feed conversion ratio of fattening lambs and kids. However, YC supplementation reduced meat/bone ratio and tissue protein content, but increased fat content in carcasses of fattening Awassi lambs, but not in fattened Shami kids.     

Effects of fibre-degrading enzymes in combination with different fibre sources on ileal and total tract nutrient digestibility and fermentation products in pigs

ABSTRACT

The study was conducted to determine effects of a complex of fibre-degrading enzymes (xylanase, cellulase and β-glucanase) on nutrient digestibility, fibre fermentation and concentrations of short chain fatty acids (SCFA) at different parts of digestive tract in pigs fed different fibre-rich ingredients. A total of 36 barrows fitted with T-cannulas in the distal ileum (initial body weight of 41.1 ± 2.7 kg) were randomly allotted to six dietary treatments with three different high-fibre diets including maize bran (MB), sugar beet pulp (SBP) and soybean hulls (SH) with or without supplementation of fibre-degrading enzymes. Enzyme supplementation improved (p < 0.05) apparent ileal digestibility (AID) of dietary gross energy (GE), crude protein, dry matter (DM), organic matter (OM), total dietary fibre (TDF), neutral detergent fibre (NDF) and apparent total tract digestibility (ATTD) of dietary GE, DM, OM, TDF, insoluble dietary fibre (IDF) when pigs were fed MB, SBP or SH diets. When compared to the SBP and SH diets, the AID of GE, DM, ash, OM and NDF in diet MB was higher (p < 0.05), but the hindgut disappearance and ATTD of nutrients, except for ether extract and crude ash, were lower (p < 0.05). Enzyme supplementation increased acetate and total SCFA concentrations in ileal digesta and faeces of pigs. In conclusion, enzyme addition improved IDF fermentation and SCFA concentration in the whole intestine of pigs, and there was a large variation of digestibility of fibre components among MB, SH and SBP owing to their different fibre composition. Therefore, fibre-degrading enzymes should be applied to fibrous diets to improve efficient production of swine, especially considering low fibre digestibility of fibre-rich ingredients.     

Effects of fibre on digestibility and passage time in callithricidae

The effects of fibre in a pelleted diet on food intake, digestibility of crude fibre, dry matter and energy, on passage time and consistency of faeces were studied in 2 species of Callithricidae, Callithrix jacchus and Saguinus fuscicollis. Coarse cellulose, microcellulose, wheat bran and shrimp meal (chitin = crude fibre) were tested in diets containing 2,4 and 6% total crude fibre, respectively. Digestibility and passage time were determined by inclusion of 0.5% Cr2O3 in the diet. Both celluloses had little influence on the digestibility of energy and dry matter. Digestibility of crude fibre was very low. Wheat bran led to evident depression of energy and dry matter digestibility. High digestibility of crude fibre occurred at the higher levels of inclusion in the diet. Shrimp meal was highly digested with little influence on digestibility of energy and dry matter, indicating considerable degradation of chitin. Wheat bran showed a marked effect, while microcellulose had no effect on passage time, consistency and volume of faeces.     

Saccharomyces cerevisiae as a probiotic feed additive to non and pseudo-ruminant feeding: a review

The production of livestock and poultry faces major challenges to meet the global demand for meat and dairy products and eggs due to a steady increase in the world’s population and the ban of antibiotics in animal production. This ban has forced animal nutritionists to seek for natural alternatives to antibiotics. In this context, the yeast Saccharomyces cerevisiae has received considerable attention in the last decade. It has been reported that feed supplementation with live yeast cells improve feed efficiency, enhance feed digestibility, increase animal performance, reduce the number of pathogenic bacteria, improve animal health and reduce the negative environmental impacts of livestock production. The current review sheds light on the effects of the use of live S. cerevisiae cells in the diets of nonruminant and pseudo-ruminant’s animals and the mechanisms by which they exert its effects. This review work revealed that the addition of S. cerevisiae in poultry feed causes a phenomenon called competitive exclusion of pathogenic bacteria capable of causing disease adhere to the yeast surface, and so removing a large amount of harmful micro-organisms and allowing the Animal defend more effectively, the production of antimicrobial agents, the balancing the gut microbiota and stimulation of host adaptive immune system and improving gut morphological structure, thus these benefits are reflected on the overall poultry health. In addition, in the presence of live S. cerevisiae cells, the immunity of rabbits was improved due to the high number of white blood cell. In addition, apparent digestibility of acid and neutral detergent fibre was improved in horses and rabbits. Saccharomyces cerevisiae in pig diets augment mucosal immunity by increasing IgM and IgA activity against pathogens, enhance intestinal development and function, adsorb mycotoxins, modulate gut microbiota and reduce postweaning diarrhoea.     

Effects of linseed lipids fed as rolled seeds, extruded seeds or oil on organic matter and crude protein digestion in cows

Effects of fatty acids of linseed in different forms, on ruminal fermentation and digestibility were studied in dry cows fitted with ruminal and duodenal cannulas. Four diets based on maize silage, lucerne hay and concentrates (65/10/25 dry matter (DM)) were compared in a 4 × 4 Latin square design experiment where the diets were: control diet (C), diet RL supplied 75 g/kg DM rolled linseeds, diet EL supplied 75 g/kg DM extruded linseeds, and diet LO supplied 26 g/kg DM linseed oil and 49 g/kg DM linseed meal. The diets did not differ in total organic matter (OM) and fibre digestibility, in forestomach and intestinal OM digestibility, and in duodenal N flow. Microbial N duodenal flow tended to be lower for RL versus C diet (P<0.1). Extrusion did not reduce ruminal crude protein (CP) degradation in vivo and in situ. Volatile fatty acid concentration and pattern, and protozoa concentration in the rumen, did not vary among diets. Results confirm the absence of a negative effect of a moderate supply of linseed on rumen function, as well as no effect of extrusion on its ruminal CP degradability.     

The intake and digestion of maize silage-based diets by dairy cows and sheep

Six lactating cows, 6 dry cows and 6 wether sheep were fed ad libitum on diets of maize silage, maize silage plus lucerne, or maize silage plus lucerne plus wheat. Faeces and urine collections allowed for the determination of digestibility of dry matter, organic matter and nitrogen, and balances of nitrogen and water.

Voluntary feed intakes were highest and digestibility values were lowest in lactating cows. The addition of lucerne reduced organic matter digestibility in dry cows, but not in lactating cows or sheep. The addition of wheat decreased intake in dry cows and sheep, but not in lactating cows. Production of milk, protein, solids-not-fat and total solids increased with dietary quality, but there was a depression in milk fat content as a result of wheat supplementation.

The ranking of the 3 diets on the basis of feed intake differed with each class of livestock, but lactating cows and sheep gave the same ranking on the basis of organic matter digestibility.     

The effect of replacing rice straw with dry wormwood (Artemisia sp.) on intake,digestibility, nitrogen balance and ruminal fermentation characteristics in sheep

This study examined the effect of substituting dry wormwood (Artemisia sp.) for rice straw in sheep diets on intake and apparent digestibility in vivo, nitrogen (N) balance and ruminal fermentation characteristics. Four Corriedale×Polwarth sheep (51.7 ± 1.3 kg) were individually housed in metabolism cages and fed diets (ad. libitum) with a 70:30 forage to concentrate ratio (DM basis), in which the basal rice straw was substituted with 0 (Control), 30 (LW), 50 (MW) or 100 (HW) g/kg of dry wormwood. The experimental design was a 4×4 latin square design in which 10 days of dietary adaptation was followed by 6 days of total feces and urine collection in each period. Rumen fluid was collected from a stomach tube at −0.5, 0.5, 1, 2, 4, and 8 h after the morning feed on day 6 of each collection period and analyzed for volatile fatty acids (VFA). The intakes of dry matter (DM), organic matter intake (OM), crude protein (CP), ether extract (EE), neutral detergent fibre (NDF) and acid detergent fibre (ADF) were higher (P<0.05) in sheep fed diets containing wormwood, than those fed the Control diet. Compared to the Control diet, CP digestibility was higher (P<0.05) in sheep fed MW and N intake, retained N, EE digestibility, urinary purine derivatives and microbial N yield were higher (P<0.05) in sheep fed diets, containing wormwood. Rumen pH was unaffected by treatment. Rumen NH₃-N and VFA concentrations were similar across treatments except that most values for diets containing wormwood were higher (P<0.05) than those for the control diet within the first 2 h of feeding. The non-glucogenic acid ratio was also similar across Control, LW and MW treatments, but it was generally lower in MW versus the Control treatment. In conclusion, substituting wormwood for rice straw in the sheep diets increased feed intake, rumen fermentation, in vivo digestibility, N retention and microbial N yield, particularly at the medium and high levels of wormwood inclusion.     

Diallyl disulphide and lovastatin: effects on energy and protein utilisation in, as well as methane emission from, sheep

Currently research on feed supplementation with natural compounds to improve energy and protein utilisation and to mitigate the greenhouse gas methane in ruminants is intensively pursued. Two compounds, diallyl disulphide (DADS), an important component of garlic oil, and lovastatin, an inhibitor of a key enzyme of methanogenic Archaea, were selected on the basis of their in vitro anti-methanogenic potential. In three 23-day experimental runs, six sheep received hay and concentrate in a duplicate 3 x 3 Latin square design. The concentrate was either not supplemented or supplemented with either 4 g DADS or 80 mg lovastatin per kg of total dietary dry matter. There were no refusals of concentrate for any treatment. Respiratory measurements were conducted on experimental days 7/8 (Period 1) and days 17/18 (Period 2). Relative to the control, digestibility of neutral detergent fibre (NDF) tended to increase (p = 0.09) with DADS by 14%. This was associated with an increased (p = 0.07) body energy retention of the animals. Effects on nitrogen balance and ruminal fermentation traits were never significant. No influence of supplements or period was found on total daily CH4 production which averaged at 28.6 g per sheep. However, across both periods the amount of CH4 produced per kg NDF digested was lower (-8%; p = 0.02) with DADS than without supplementation, and the lovastatin treatment ranged in between. In conclusion, the study demonstrated a certain potential of DADS to improve fibre digestion and body energy retention and to limit CH4 formation in relation to digestible fibre intake, while lovastatin remained ineffective.     

Comparative effects of feeding citrus pulp and grape pomace on nutrient digestibility and utilization in steers

Feedlot beef production in tropics and subtropics is being limited by shortage of feed ingredients due to prolonged droughts resulting in high prices of cereal grains and reduced profitability. To alleviate feed shortages and increase profitability for the feedlot industry, it is important to explore underutilized non-conventional resources such as fruit by-products. The current study compared the nutrient intake, digestibility and utilization effects of feeding either 150 g/kg of dried citrus pulp (DCP) or grape pomace (DGP) as alternative dietary fibre sources to 7 months-old Angus steers (281 ± 15.7 kg) under feedlot conditions. Twenty-four steers were assigned to three dietary treatments (8 steers/treatment) in a completely randomised design. Each steer was treated as an experimental unit. Steers were adapted to diets for 21 d followed by 7 d of sample collection during which nutrient intake, digestibility, rumen fermentation parameters, nitrogen retention and microbial N supply were determined. All the data were analysed using the GLIMMIX procedures. Overall, steers fed DGP had the greatest dry matter intake (DM), organic matter (OM) crude protein (CP), ash free neutral detergent fibre (aNDFom), ether extract (EE) and starch intake followed by DCP and control (CON) diets (P ≤ .05). Apparent digestibilities of DM, OM and aNDFom were higher (P ≤ .05) for DCP diet compared to DGP and CON diets. Feeding DCP and DGP diets increased ruminal concentrations of total volatile fatty acids, acetate and isovalerate, and acetate to propionate ratio, and reduced propionate concentrations compared to the CON diet (P ≤ .05). The steers fed the CON diet had the greatest urinary excretions of allantoin, uric acid and total purine derivatives followed by those fed the DCP and DGP diets (P ≤ .05). Nitrogen intake, faecal nitrogen (N), N retention and N efficiency utilization were in the order of DGP > DCP > CON diets (P ≤ .05). Overall, feeding DGP as alternative fibre source to wheat bran improved nutrient intake, retention and efficiency of N utilization but reduced apparent nutrient digestibility compared to DCP. Current finding suggests that DGP may be a better fibre substitute for wheat bran in beef diets than DCP.     

溶菌酶对瘤胃体外发酵、甲烷生成及微生物菌群结构的影响

【目的】通过体外静态模拟瘤胃发酵法研究溶菌酶对瘤胃发酵、甲烷生成及微生物菌群结构的影响。【方法】采用单因素多水平试验设计,溶菌酶添加水平分别为0(L-0,对照组)、0.1 mg/100 m L(L-0.1)、1 mg/100 m L(L-1)、10 mg/100 m L(L-10)和100 mg/100 m L(L-100),定时测定产气量和甲烷产量,培养24 h后,发酵液用于发酵参数和微生物菌群数量的q PCR测定,其中L-0、L-1和L-100三个组发酵液同时进行16S r RNA基因Illumina高通量测序。【结果】与对照组相比,低剂量溶菌酶添加(L-0.1组)不影响甲烷产量、氨氮浓度、干物质消失率、有机物消失率和总挥发性脂肪酸等瘤胃发酵参数(P0.05);随着剂量提高,L-1处理组甲烷产量、氨氮浓度显著降低(P0.05),丙酸浓度显著增加(P0.05),并且干物质消失率、有机物消失率和总挥发性脂肪酸不受影响(P0.05);而较高剂量组(L-10和L-100组)虽然甲烷产量显著降低,丙酸浓度显著增加(P0.05),但干物质消失率和有机物消失率也显著降低(P0.05)。q PCR结果显示高剂量组(L-100组)总菌、原虫、甲烷菌数量与对照组相比显著降低(P0.05),而L-0.1、L-1和L-10组总菌、真菌和原虫数量与对照组相比均无显著变化(P0.05)。高通量测序主成分分析(PCA)显示对照组与溶菌酶添加组间瘤胃细菌组成的明显区分,说明添加溶菌酶显著改变了瘤胃细菌菌群结构。溶菌酶通过增加月形单胞菌和琥珀酸弧菌等丙酸生成菌的相对丰度,使更多的氢被用于生成丙酸,导致甲烷产量降低;溶菌酶可抑制普雷沃氏菌和拟杆菌属等蛋白降解菌的生长,进而减少蛋白质过度降解,降低氨氮浓度。【结论】添加适宜浓度(1 mg/100 m L)的溶菌酶可通过调控瘤胃微生态改变瘤胃发酵模式,降低瘤胃甲烷和氨的生成,短期内并不影响饲料消化。     

Effects of folic acid supplementation to rations differing in the concentrate to roughage ratio on ruminal fermentation, nutrient flow at the duodenum, and on serum and milk variables of dairy cows

The present study was undertaken to determine the effects of dietary folic acid (FOL) supplementation on ruminal fermentation, duodenal nutrient flow, serum and milk variables, and on B-vitamin concentration in serum. The study was divided into two experiments: in Exp. 1 the forage to concentrate (F:C) ratio of the diet (DM basis) was 34:66 (high concentrate, HC), while in Exp. 2 the F:C ratio was 66:34 (high forage, HF). In addition, the cows received 0 or 1 g FOL/d. In Exp. 1, two German Holstein cows equipped with cannulas in the dorsal sac of the rumen and in the proximal duodenum were dry and five were lactating (186 +/- 144 days in milk); in Exp. 2 four cows were dry and four were lactating (165 +/- 57 days in milk). In cows fed the HC diet, FOL supplementation decreased the ruminally-fermented organic matter. Thus, less energy was available for ruminal microorganisms, which resulted in a reduced microbial crude protein flow at the duodenum. Feeding the HF diet, FOL supplementation only increased the apparent ruminal digestibility of acid detergent fibre (ADF). With the HF diet, FOL had no influence on the serum levels of glucose, non-esterified fatty acids, beta-hydroxybutyrate, urea, thiamine, riboflavin, pyridoxal-5'-phosphate, pyridoxic acid, pyridoxal, pyridoxine, pyridoxamine, pantothenic acid, nicotinamide or nicotinic acid, whereas supplementing FOL to the HC diet lowered the serum glucose and riboflavin levels. In both experiments, the supplementation of FOL had no effects on milk composition. Folic acid supplementation to both diets increased the concentrations of serum 5-methyl-tetrahydrofolate. However, no beneficial effects to dairy cows were obvious. Therefore, to achieve certain results, studies with a higher number of non-fistulated cows would be necessary.     

Effects of the supplementation of distillers’ grape residues on ruminal degradability,whole tract digestibility and nitrogen metabolism in sheep

ABSTRACT

Five ruminally and duodenally cannulated Kazakh male lambs (30 ± 2.75 kg) maintained singly in a metabolic cage were used in a 5 × 5 Latin square experiment to investigate the effect of supplementing a ration with five different levels of distillers’ grape residue (DGR) on ruminal degradability, whole tract digestibility and nitrogen (N) metabolism of growing lambs. The rations were isoenergetic and isonitrogenous and contained 0, 3.85, 7.70, 11.55 and 15.41% DGR (DM basis). Each experimental period lasted for 18 d: 10 d for adaptation to the dietary treatment and 8 d for faecal, urinary, ruminal and duodenal digesta sample collections. The outflow rate of ruminal digesta increased (p = 0.032) linearly with the increased level of dietary neutral detergent fibre content, caused by the supplementation of DGR. As a result, the effective degradability of dry matter and crude protein decreased significantly with the treatments. Although the dietary intake of N, duodenal flow of total N, and the endogenous N at the duodenum were not affected by experimental treatments, N fractions in the digesta were altered. Ruminal microbial N decreased (p < 0.01) linearly; in contrast, ruminal un-degradable protein increased linearly (p < 0.01) in response to the increased addition of DGR. Although there was no significant difference in faecal N among treatments, N retention was increased linearly (p = 0.014), owing to the remarkable reduction (p = 0.016) of urinary N excretion with an increasing level of DGR. The results indicate that the DGR has some potential benefits of increasing the supply of bypass protein and of improving the utilisation efficiency of N for sheep. Therefore, the supplementation of DGR in ruminant feeding is recommended at levels not exceeding 10% of the diet.