Effects of dietary chromium picolinate and peppermint essential oil on growth performance and blood biochemical parameters of broiler chicks reared under heat stress conditions

A study was conducted using 240 female day-old broiler chicks to evaluate the effects of dietary chromium picolinate (CrPic), peppermint essential oil (P.mint), or their combination on growth performance and blood biochemical parameters of female broiler chicks raised under heat stress conditions (HS, 23.9 to 38 °C cycling). Average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were obtained from 1 to 42 days of age. Furthermore, at the end of the experiment (day 42), birds were bled to determine some blood biochemical parameters and weighed for final body weight (BW). ADFI, ADG, and BW were not influenced significantly by dietary CrPic and P.mint (P?>?0.05). A significant interaction between dietary CrPic and P.mint on FCR (P?=?0.012) was detected. FCR significantly decreased in chicks fed the diet including both CrPic and P.mint compared with the CrPic group. Significant interaction between dietary P.mint and CrPic on serum concentrations of triglycerides, glucose, and albumin were observed (P?<?0.05), but the other measured blood biochemical parameters were not statistically affected by dietary treatments (P?>?0.05). The serum concentrations of glucose, triglycerides were decreased (P?<?0.05) in broilers fed the diet including both CrPic and P.mint. Plasma chromium (Cr) content increased significantly (P?<?0.05) in birds fed the CrPic-included diet compared with the control group (P?<?0.05). From the results of the present experiment it can be concluded that dietary supplementation with combined P.mint and CrPic could have beneficial effects on some blood biochemical parameters of female chicks reared under heat stress conditions.     

Effects of the different levels of dietary trace elements from organic or inorganic sources on growth performance,carcass traits,meat quality,and faecal mineral excretion of broilers

ABSTRACT

This experiment was conducted to evaluate the effects of different sources and levels of trace elements on growth performance, carcass composition and mineral excretion levels of broilers. In a completely randomised experimental design, 900 one-day-old male Ross-308 broilers were assigned to 5 treatments, with 6 replicates of 30 birds each. The control group (CITE) was fed with a basal diet containing regular inclusion levels of inorganic trace elements. Treatment groups were supplied with reduced levels (30% and 50% of the regular level) of inorganic (ITE) or organic trace elements (OTE), respectively. Groups 50% ITE, 30% OTE and 50% OTE diets had equivalent average daily gain (ADG), average daily feed intake (ADFI), feed to gain ratio (F/G ratio) and mortality rate compared with group CITE in any phase. However, compared with group CITE chicks in group 30% ITE have lower ADG and ADFI and higher F/G ratio. The carcass yields were not affected by dietary treatments. Compared with group CITE, in groups 30% ITE, 50% ITE, 30% OTE and 50% OTE the shear force values of the breast muscle were only 71.8%, 83.4%, 63.5% and 59.4% (p < 0.05), respectively. Birds received diets containing reduced levels of trace elements had diminished excretions of Mn and Zn throughout the entire period (p < 0.01). In conclusion, the reduced supplementation of trace elements had no or slightly negative impact on growth performance, carcass yield and meat quality, but decreased faecal mineral excretion. Moreover, the trace element supply as OTE played a limited role on performance and excretion and was only partly beneficial for animal performance in case the trace element supply was reduced to 30%.     

Meta-analysis of feed intake and growth responses of growing pigs after a sanitary challenge

Sanitary challenges negatively affect feed intake and growth, leading to a negative impact on animal well-being and economic losses. The aim of this study was to carry out a meta-analysis to quantify the dynamic feed intake and growth responses of growing pigs after a sanitary challenge. A database was constructed using 122 published experiments reporting the average daily feed intake (ADFI) and the average daily gain (ADG) of pigs subjected to one of six sanitary challenges: digestive bacterial infections, poor housing conditions, lipopolysaccharide (LPS) challenges, mycotoxicoses, parasitic infections and respiratory diseases. The responses to experimental challenges were calculated relative to that of a control group. Statistical analyses were carried out for each challenge to quantify the mean and the dynamic responses in feed intake and growth and to identify the basis of the reduction in growth (i.e. reduction in feed intake or reduction in feed efficiency related to changes in maintenance requirements). All challenges resulted in a reduction in ADFI and ADG, with the strongest responses for mycotoxicoses, respiratory diseases and digestive bacterial infections (8% to 23% reduction in ADFI and 16% to 29% reduction in ADG). The reduction in ADG was linearly related to the reduction in ADFI for digestive bacterial infections, LPS challenge, parasitic infections and respiratory diseases. For poor housing conditions and mycotoxicoses, the relationship was curvilinear. A 10% reduction in ADFI resulted in a reduction in ADG varying from 10% for mycotoxicoses to 43% for digestive bacterial infections. More than 70% of the reduction in ADG could be explained by the reduction in ADFI for mycotoxicoses, LPS challenge and respiratory diseases. For challenges associated with the gastrointestinal tract, a large part of the reduction in ADG was due to an increase in maintenance requirements, suggesting digestive and metabolic changes. A dynamic pattern in the reduction in feed intake and growth rate could be identified for digestive bacterial infections, mycotoxicoses and respiratory diseases. For digestive bacterial infections and mycotoxicoses, pigs did not fully recover from the challenge during the experimental period. The results of this study can be used to quantify the effects of a sanitary challenge in growth models of pigs.     

Development of equations to predict the influence of floor space on average daily gain,average daily feed intake and gain : feed ratio of finishing pigs

Floor space allowance for pigs has substantial effects on pig growth and welfare. Data from 30 papers examining the influence of floor space allowance on the growth of finishing pigs was used in a meta-analysis to develop alternative prediction equations for average daily gain (ADG), average daily feed intake (ADFI) and gain : feed ratio (G : F). Treatment means were compiled in a database that contained 30 papers for ADG and 28 papers for ADFI and G : F. The predictor variables evaluated were floor space (m²/pig), k (floor space/final BW^0.67), Initial BW, Final BW, feed space (pigs per feeder hole), water space (pigs per waterer), group size (pigs per pen), gender, floor type and study length (d). Multivariable general linear mixed model regression equations were used. Floor space treatments within each experiment were the observational and experimental unit. The optimum equations to predict ADG, ADFI and G : F were: ADG, g=337.57+(16 468×k)−(237 350×k²)−(3.1209×initial BW (kg))+(2.569×final BW (kg))+(71.6918×k×initial BW (kg)); ADFI, g=833.41+(24 785×k)−(388 998×k²)−(3.0027×initial BW (kg))+(11.246×final BW (kg))+(187.61×k×initial BW (kg)); G : F=predicted ADG/predicted ADFI. Overall, the meta-analysis indicates that BW is an important predictor of ADG and ADFI even after computing the constant coefficient k, which utilizes final BW in its calculation. This suggests including initial and final BW improves the prediction over using k as a predictor alone. In addition, the analysis also indicated that G : F of finishing pigs is influenced by floor space allowance, whereas individual studies have concluded variable results.     

Effect of Dietary Supplementation with Copper Sulfate or Tribasic Copper Chloride on the Growth Performance, Liver Copper Concentrations of Broilers Fed in Floor Pens, and Stabilities of Vitamin E and Phytase in Feeds

An experiment was conducted using a total of 840, 1-day-old, Arbor Acres commercial male broilers to compare copper (Cu) sulfate and tribasic Cu chloride (TBCC, Cu₂(OH)₃Cl) as sources of supplemental Cu for broilers fed in floor pens. Chicks were randomly allotted to one of seven treatments for six replicate pens of 20 birds each, and were fed a basal corn–soybean meal diet (10.20 mg/kg Cu) supplemented with 0, 100, 150, or 200 mg/kg Cu from either Cu sulfate or TBCC for 21 days. Chicks fed 200 mg/kg Cu as TBCC had a higher (P?<?0.05) average daily gain (ADG) than those consuming other diets. Liver Cu contents of broilers fed diets supplemented with TBCC were numerically lower (P?>?0.05) than those of broilers fed diets supplemented with Cu sulfate. The vitamin E contents and the phytase activities in the feed fortified with TBCC were higher (P?<?0.01) and numerically higher (P?>?0.05) compared with those in the feeds fortified with Cu sulfate stored at room temperature, respectively. The vitamin E contents in liver and plasma of broilers fed diets supplemented with TBCC were higher (P?<?0.05) than those of birds fed diets supplemented with Cu sulfate. This result indicates that TBCC is more effective than Cu sulfate in improving the growth of broilers fed in floor pens, and it is chemically less active than Cu sulfate in promoting the undesirable oxidation of vitamin E in feeds.     

Variation in faecal digestibility values related to feed efficiency traits of grower-finisher pigs

Providing pigs a diet that matches their nutrient requirements involves optimizing the diet based on the nutrient digestibility values of the considered feed ingredients. Feeding the same quantity of a diet to pigs with similar BW but with different requirements, however, can result in a different average daily gain (ADG) and backfat thickness (BF) between pigs. Digestibility may contribute to this variation in efficiency. We investigated variation in feed efficiency traits in grower-finisher pigs associated with variation in faecal digestibility values, independent of feed intake at the time of measuring faecal digestibility. Considered traits were ADG, average daily feed intake (ADFI), feed conversion ratio (FCR), BF and residual feed intake (RFI). Feed intake, BW, and BF data of one hundred and sixty three-way crossbreed grower-finisher pigs (eighty female and eighty male) were collected during two phases, from day 0 of the experiment (mean BW 23 kg) till day 56 (mean BW 70 kg) and from day 56 to slaughter (mean BW 121 kg). Pigs were either fed a diet based on corn/soybean meal or a more fibrous diet based on wheat/barley/by-products, with titanium dioxide as indigestible marker. Faecal samples of one hundred and five pigs were collected on the day before slaughter and used to determine apparent faecal digestibility of DM, ash, organic matter (OM), CP, crude fat (CFat), crude fibre (CF), and to calculate the digestibility of nonstarch polysaccharides (NSPs) and energy (E). The effects of diet, sex and covariate feed intake at sampling (FIs) on faecal digestibility values were estimated and were significant for all except for CFat. Faecal digestibility values of each individual pig determined at the day before slaughter, corrected for diet, sex and FIs, were used to estimate their association with ADG, ADFI, FCR, BF, and RFI. In the first phase, a one percent unit increase in faecal digestibility of DM, ash, OM, E, CP, CFat, CF, NSP, and Ash individually was related to 0.01–0.03 unit reduction in FCR and 6–23 g/day reduction in RFI. A unit increase in CP digestibility was related to 0.1 mm increase in BF and 10 g/day increase in ADG. In the second phase, a one percent unit increase in faecal digestibility of DM, CP and Ash was related to a decrease of 16–20 g/day in RFI. In conclusion, the relationship between variation in feed efficiency traits and faecal digestibility values is different across the developmental stages of a pig.     

Meta-analysis of phosphorus utilisation by broilers receiving corn-soyabean meal diets: influence of dietary calcium and microbial phytase

Pollution relative to phosphorus excretion in poultry manure as well as the soaring prices of phosphate, a non-renewable resource, remain of major importance. Thus, a good understanding of bird response regarding dietary phosphorus (P) is a prerequisite to optimise the utilisation of this essential element in broiler diets. A database built from 15 experiments with 203 treatments was used to predict the response of 21-day-old broilers to dietary non-phytate P (NPP), taking into account the main factors of variation, calcium (Ca) and microbial phytase derived from Aspergillus niger, in terms of average daily feed intake (ADFI), average daily gain (ADG), gain to feed (G:F) and tibia ash concentration. All criteria evolve linearly (P < 0.001) and quadratically (P < 0.001) with dietary NPP concentration. Dietary Ca affected the intercept and linear component for ADG (P < 0.01), G:F (P < 0.05) and tibia ash concentration (P < 0.001), whereas for ADFI, it affected only the intercept (P < 0.01). Microbial phytase addition impacted on the intercept, the linear and the quadratic coefficient for ADFI (P < 0.01), ADG (P < 0.001) and G:F (P < 0.05), and on the intercept and the linear component (P < 0.001) for tibia ash concentration. An evaluation of these models was then performed on a database built from 28 experiments and 255 treatments that were not used to perform the models. Results showed that ADFI, ADG and Tibia ash concentration were predicted fairly well (slope and intercept did not deviate from 0 to 1, respectively), whereas this was not the case for G:F. The increase in dietary Ca concentration aggravated P deficiency for all criteria while phytase addition had a positive effect. The more P deficiency was marked, the more the bird response to ADFI, ADG, G:F and tibia ash concentration was exacerbated. It must also be considered that even if the decrease in dietary Ca may improve P utilisation, it could in turn become limiting for bone mineralisation. In conclusion, this meta-analysis provides ways to reduce dietary P in broiler diets without impairing performance, taking into account dietary Ca and microbial phytase.     

Impact of Porcine Epidemic Diarrhea on Performance of Growing Pigs

The impact of porcine epidemic diarrhea virus (PEDv) infection on the US pork industry has mainly been attributed to the mortality that it causes in suckling piglets, and, consequently, much effort has been invested in the quantification of its effect in sow farms. However, no information on the performance of surviving pigs that were exposed to the PEDv as piglets is available. Here, a retrospective cohort study to evaluate the impact of porcine epidemic diarrhea virus (PEDv) infection on growing pigs’ performance, as indicated by mortality, average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) was performed using production records from weaned pigs in nursery and wean-to-finish sites from sow farms that became PEDv-infected between May 2013 and June 2014. Production records from the first batch of growing pigs weaned in infected flows after the PEDv outbreak (“infected batches”) were compared with those from pigs weaned within the previous 14 to 120 days (“control batches”). Performance records from infected and control batches, paired by flow, were compared using non-parametric paired tests. Mortality, ADG and FCR were significantly different in PEDv-positive (infected) compared with PEDv-negative (control) batches, with a mean increase of mortality and FCR of 11% and 0.5, respectively, and a decrease of ADG of 0.16 lb/day. Our results demonstrate a poorer performance of growing pigs weaned after a PEDv outbreak compared with those weaned within the previous 14-120 days, suggesting that in addition to the mortality induced by PEDv in suckling pigs, the disease also impairs the performance of surviving pig. These findings help to quantify the impact of PEDv infection in the US and, ultimately, contribute to efforts to quantify the cost-effectiveness of disease prevention and control measures.     

Requirement of standardized ileal digestible valine to lysine ratio for 8- to 14-kg pigs

The objective was to define the Val requirement for weaned piglets in the context of reducing the dietary protein content. A dose–response experiment was conducted to estimate the standardized ileal digestible (SID) Val to Lys ratio required to support the optimum growth of post-weaned piglets. In this study, 96 pigs weighing 8 kg were allotted to one of six dietary treatments (16 pigs for each dietary treatment) and were housed individually. Diets were formulated to provide 0.58, 0.62, 0.66, 0.70, 0.74 and 0.78 SID Val : Lys by adding graded levels of crystallinel-Val to the 0.58 SID Val : Lys diet. Lysine was sub-limiting and supplied 90% of the recommendation (10.95 g SID Lys/kg equal to 11.8 g/kg total Lys). Average daily feed intake (ADFI), average daily gain (ADG) and gain to feed ratio (G : F) were determined during a 14-day period ofad libitum feeding. Blood and urine samples were taken at the end of each week (day 7 and 14 of the experiment) 3 h after feeding the experimental diets. The maximum ADFI and ADG were obtained in pigs fed the 0.78 SID Val : Lys diet; it was not different from the results of pigs fed 0.70 SID Val : Lys diet. The highest G : F was obtained in pigs fed 0.70 SID Val : Lys. The plasma concentration of Val increased linearly (P<0.001) as the dietary SID Val : Lys increased. The increasing dietary Val : Lys also resulted in a linear increase in Cys (P<0.001) and a quadratic increase in Arg (P=0.003), Lys (P=0.05) and Phe (P=0.009). The plasma Gly showed a quadratic decrease (P=0.05) as the dietary Val : Lys increased. Neither plasma nor urinary urea to creatinine ratio was affected by treatment. The minimum SID Val : Lys required to maximize ADFI, ADG and G : F was estimated at 0.67 SID Val : Lys by a broken-line model, and at 0.71 SID Val : Lys by a curvilinear plateau model. The Val deficiency caused a reduction in ADFI, and Val supplementation above the requirement did not impair animal performance. In conclusion, 0.70 SID Val : Lys is suggested as the Val requirement for 8 to 14 kg individually housed pigs.     

Investigation on the effect of different levels of dried sweet orange (Citrus sinensis) pulp on performance,carcass characteristics and physiological and biochemical parameters in broiler chicken

Utilization of agricultural by-products in animal nutrition is a matter of great concern. Dried sweet orange (Citrus sinensis) pulp (DCSP) is a potential source of valuable nutrients and natural antioxidants for poultry feed. In the experiment, a feeding trial was conducted in order to investigate the effect of different levels of dried orange residues in diet on broiler growth performance, carcass characteristics, blood metabolites, humoral immunity, and cecum microbial population. A total of 200 one day experimental broiler chicks were distributed into a completely randomized design (CRD) which included 5 dietary treatments with 4 replicates per each treatment and 10 birds fed in each replicate. The experimental treatments consist of a control group (without additive), 0.5%, 1.0%, 1.5%, and 2% of DCSP (residue) in diet. Weight gain, feed intake and feed conversion ratio (FCR) were measured. Blood parameters and carcass traits were measured in the postnatal 35th day. The highest level of dried orange residues in treatment 5 (T5) had significantly increased the feed intake and body weight of broilers in groups and overall during the rearing period (P > 0.05). Different levels of dried orange residues had no significant effect on chicken FCR. Using of dried orange residues significantly decreased the liver and abdominal fat of broilers (P < 0.05). T5 has also significantly lower level of triglyceride than the control (T1) and treatment 2 (T2) (P < 0.05). In conclusion, the use of dried orange residues improved some performance (e.g. feed intake and body weight gain), decreased liver and abdominal fat and also serum triglyceride level in broiler chicken.     

Effect of high dietary copper on weight gain and neuropeptide Y level in the hypothalamus of pigs

An experiment was performed to examine the effect of dietary copper supplementation on weight gain, neuropeptide Y (NPY) concentration and NPY mRNA expression level in the hypothalamus of pigs. Forty-five crossbred pigs were randomly assigned to three groups of 15 pigs, each comprising five replicates of 3 animals. Pigs were allocated to diets that contained 10 mg/kg (as a control), 125 and 250 mg/kg copper as CuSO₄. Live weight gain and feed conversion efficiency was determined at the end of the experiment and five pigs, selected at random from each group, were slaughtered and the hypothalami collected for determination of NPY concentration and NPY mRNA expression level. The results showed that average daily gain (ADG) and average daily feed intake (ADFI) were higher and feed:gain (F:G) ratio was lower in pigs fed the diets with 125 and 250 mg/kg copper (P<0.05), respectively, than in pigs fed a diet with 10 mg/kg copper, but that there was no statistically significant difference in growth performance between animals of the 125 mg/kg and the 250 mg/kg copper groups. Furthermore, pigs fed diets with 125 and 250 mg/kg copper had higher NPY concentrations and NPY mRNA expression levels in their hypothalamus than control animals. The data indicated that 125 and 250 mg/kg copper gave similar responses in terms of weight gain, whilst high dietary copper could enhance NPY concentration and NPY mRNA expression level in the hypothalamus of pigs. High dietary copper appears to increase feed intake and promote weight gain by enhancing NPY concentration and NPY mRNA expression level in the hypothalamus of pigs.     

Pig acute-phase protein levels after stress induced by changes in the pattern of food administration

A total of 240 pigs, 74 days old, half boars and half females, were included in a trial designed to assess the effect of the stress caused by changes in the pattern of food administration on the concentration of acute phase proteins (APP) and productive performance parameters. Half of the animals (pigs fed ad libitum, AL group) had free access to feed, while the rest were fed following a disorderly pattern (DIS group), in which animals had alternating periods of free access to feed and periods of no feeding, when food was removed from the feeder. The periods of free access to feed (two daily periods of 2-h duration) were randomly assigned, and varied from day to day. Total feed supplied per day was identical in both groups, and exceeded the minimal amount required for animals of these ages. Pen feed intake, individual body weights and the main positive pig APP pig major acute phase protein (Pig-MAP), haptoglobin, serum amyloid A (SAA), C-reactive protein (CRP), and the negative APP apolipoprotein A-I (ApoA-I) and transtherytin were determined every 2 weeks during the period 76 to 116 days of age. Animals fed ad libitum had better average daily gain (ADG) than DIS animals in the whole experimental period (P < 0.01) but the differences in ADG were only produced in the two first experimental sub-periods (60 to 74 and 74 to 116 days of age), suggesting that the stress diminished when the animals get used to the DIS feeding. Interestingly differences in ADG between DIS and AL pigs were due to males, whereas no differences were observed between females. The same differences observed for ADG were found for APP. DIS males had higher Pig-MAP concentration than AL males at 74 and 116 days of age, lower ApoA-I concentration at 74 days of age and higher haptoglobin and CRP concentration at 116 days of age (P < 0.05). The results obtained in this trial show an inverse relationship between weight gain and APP levels, and suggest that APP may be biomarkers for the evaluation of distress and welfare in pigs.     

Estimation of the tryptophan requirement in piglets by meta-analysis

There is no consensus concerning the Trp requirement for piglets expressed relative to Lys on a standardized ileal digestible basis (SID Trp : Lys). A meta-analysis was performed to estimate the SID Trp : Lys ratio that maximizes performance of weaned piglets between 7 and 25 kg of BW. A database comprising 130 experiments on the Trp requirement in piglets was established. The nutritional values of the diets were calculated from the composition of feed ingredients. Among all experiments, 37 experiments were selected to be used in the meta-analysis because they were designed to express the Trp requirement relative to Lys (e.g. Lys was the second-limiting amino acid in the diet) while testing at least three levels of Trp. The linear-plateau (LP), curvilinear-plateau (CLP) and asymptotic (ASY) models were tested to estimate the SID Trp : Lys requirement using average daily gain (ADG), average daily feed intake (ADFI) and gain-to-feed ratio (G : F) as response criteria. A multiplicative trial effect was included in the models on the plateau value, assuming that the experimental conditions affected only this parameter and not the requirement or the shape of the response to Trp. Model choice appeared to have an important impact on the estimated requirement. Using ADG and ADFI as response criteria, the SID Trp : Lys requirement was estimated at 17% with the LP model, at 22% with the CLP model and at 26% with the ASY model. Requirement estimates were slightly lower when G : F was used as response criterion. The Trp requirement was not affected by the composition of the diet (corn v. a mixture of cereals). The CLP model appeared to be the best-adapted model to describe the response curve of a population. This model predicted that increasing the SID Trp : Lys ratio from 17% to 22% resulted in an increase in ADG by 8%.     

Use of yeast (<Emphasis Type="Italic">Pichia kudriavzevii</Emphasis>) as a novel feed additive to ameliorate the effects of aflatoxin B<Subscript>1</Subscript> on broiler chicken performance

The aim of this study was to evaluate the efficacy of autochthonous Pichia kudriavzevii as a novel bioadsorbent for aflatoxin B₁ (AFB₁). The selection of this yeast was based on the AFB₁ adsorption capacity previously demonstrated in vitro (Magnoli et al. 2016). One-day-old Cobb broilers (n = 160) were randomly assigned to four dietary treatments (T1: basal diet (B); T2: B + 0.1% yeast; T3: B + AFB₁, 100 μg/kg; T4: B + 0.1% yeast + AFB₁, 100 μg/kg). Performance parameters (average daily weight gain body, average daily consumption, feed conversion ratio, carcass weight, and dead weight), biochemical parameters (albumin, globulin, and albumin/globulin), liver pathological changes, and AFB₁ residual levels in the liver and excreta were evaluated. Significant differences (P < 0.05) in performance parameters were observed among treatments and controls: T3 group showed the lowest average daily body weight gain value while in T4 group, the value of this parameter increased significantly (P < 0.05). T3 and T4 groups showed the lowest and highest values for average daily feed consumption, respectively. The feed conversion ratio (FC) showed no significant differences among treatments. T3 group showed the lowest dead weight and carcass weight compared with T1 group. The biochemical parameters showed no significant differences among treatments. T3 group showed macroscopic and microscopic liver changes compared to the control. Aflatoxin B₁ levels (μg/g) were detected in broiler livers and showed significant differences among treatments (P < 0.05). In conclusion, native P. kudriavzevii incorporation (0.1%) in broiler diets containing AFB₁ was shown to be effective in ameliorating the adverse effects of AFB₁ on production.     

Partial replacement of triticale for corn grain in starter diet and its effects on performance,structural growth and blood metabolites of Holstein calves

The primary objective of this study was to examine the effects of different inclusion rates of dietary triticale replacing corn grain in starter rations of dairy calves on feed intake, average daily gain (ADG), feed efficiency, skeletal growth, fecal score, and selected blood and ruminal parameters. In all, 30 4-day-old Holstein calves (15 female and 15 male) were blocked by gender and birth weight, and then randomly allotted to three treatment groups (n=10 calves/treatment) and received either a corn-based diet without triticale (T0), or a diet containing 16% (T16) or 32% (T32) triticale (25% and 50% corn replaced by triticale, respectively) for 10 weeks. Calves were weaned on day 43 of study and remained on the study until day 70. During post-weaning period, calves fed T32 had the lowest starter intake (1.78 kg/day; P=0.02). In contrast, ADG was not affected in pre-weaning and overall periods, but calves fed T32 had a lower ADG (P=0.04) as compared with calves fed T0 in post-weaning period. No dietary effect was detected for feed efficiency. Dietary treatment did not affect heart girth and body length; however, height at wither and hip at weaning increased in calves fed triticale compared with T0. No detectable effects were observed in serum glucose and β-hydroxybutyrate. No difference was detected in blood urea nitrogen on day 35 either but on day 50 and day 70 the greatest concentration was recorded for calves fed T16. Compared with the control, ruminal ammonia concentration was increased for calves fed T32 (4.34 v. 7.50 mmol/l) and T16 (4.01 v. 8.12 mmol/l) on day 35 and day 50. No difference was detected in ruminal pH on day 35 or day 50; however, calves fed T32 had the lowest pH (6.11) at 70 days. No significant effect was detected in days scoured, respiratory score and general appearance. Under our experimental conditions, it appears that triticale at 16% dry matter (i.e. replacing corn grain up to 25%) in the starter diet does not have adverse effects on the performance and intake of calves. Therefore, substituting corn partially with triticale in calf starter diets may prove beneficial in places where corn is less abundant or its price is prohibitive. The low number of calves per treatment however may have limited the statistical power to detect significant differences among treatments, possibly affecting the results, which should be interpreted with caution.     

A genome-wide association study for feed efficiency-related traits in a crossbred pig population

Feed efficiency (FE) is one of the most important traits in pig production. However, it is difficult and costly to measure it, limiting the collection of large amount of data for an accurate selection for better FE. Therefore, the identification of single-nucleotide polymorphisms (SNPs) associated with FE-related traits to be used in the genetic evaluation is of great interest of pig breeding programs for increasing the prediction accuracy and the genetic progress of these traits. The objective of this study was to identify SNPs significantly associated with FE-related traits: average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR). We also aimed to identify potential candidate genes for these traits. Phenotypic information recorded on a population of 2386 three-way crossbreed pigs that were genotyped for 51 468 SNPs was used. We identified three loci of quantitative trait (QTL) regions associated with ADG and three QTL regions associated with ADFI; however, no significant association was found for FCR. A false discovery rate (FDR) ≤ 0.005 was used as the threshold for declaring an association as significant. The QTL regions associated with ADG on Sus scrofa chromosome (SSC) 1 were located between 177.01 and 185.47 Mb, which overlaps with the QTL regions for ADFI on SSC1 (173.26 and 185.47 Mb). The other QTL region for ADG was located on SSC12 (2.87 and 3.22 Mb). The most significant SNPs in these QTL regions explained up to 3.26% of the phenotypic variance of these traits. The non-identification of genomic regions associated with FCR can be explained by the complexity of this trait, which is a ratio between ADG and ADFI. Finally, the genes CDH19, CDH7, RNF152, MC4R, PMAIP1, FEM1B and GAA were the candidate genes found in the 1 Mb window around the QTL regions identified in this study. Among them, the MC4R gene (SSC1) has a well-known function related to ADG and ADFI. In this study, we identified three QTL regions for ADG (SSC1 and SSC12) and three for ADFI (SSC1). These regions were previously described in purebred pig populations; however, to our knowledge, this is the first study to confirm the relevance of these QTL regions in a crossbred pig population. The potential use of the SNPs and genes identified in this study in prediction models that combine genomic selection and marker-assisted selection should be evaluated for increasing the prediction accuracy of these traits in this population.     

Genetic markers on BTA14 predictive for residual feed intake in beef steers and their effects on carcass and meat quality traits

With the high cost of feed for animal production, genetic selection for animals that metabolize feed more efficiently could result in substantial cost savings for cattle producers. The purpose of this study was to identify DNA markers predictive for differences among cattle for traits associated with feed efficiency. Crossbred steers were fed a high‐corn diet for 140 days and average daily feed intake (ADFI), average daily gain (ADG), and residual feed intake (RFI) phenotypes were obtained. A region on chromosome 14 was previously associated with RFI in this population of animals. To develop markers with the highest utility for predicting an animal's genetic potential for RFI, we genotyped additional markers within this chromosomal region. These polymorphisms were genotyped on the same animals (n = 1066) and tested for association with ADFI, ADG and RFI. Six markers within this region were associated with RFI (P ≤ 0.05). After conservative correction for multiple testing, one marker at 25.09 Mb remained significant (P = 0.02) and is responsible for 3.6% of the RFI phenotypic variation in this population of animals. Several of these markers were also significant for ADG, although none were significant after correction. Marker alleles with positive effects on ADG corresponded to lower RFI, suggesting an effect increasing growth without increasing feed intake. All markers were also assessed for their effects on meat quality and carcass traits. All of the markers associated with RFI were associated with adjusted fat thickness (AFT, P ≤ 0.009) and three were also associated with hot carcass weight (HCW, P ≤ 0.003). Marker alleles associated with lower RFI were also associated with reduced AFT, and if they were associated for HCW, the effect was an increase in weight. These markers may be useful as prediction tools for animals that utilize feed more efficiently; however, validation with additional populations of cattle is required.     

Effect of liquid feeding at different water-to-feed ratios on the growth performance of growing-finishing pigs

The study examined the growth performance of pigs offered liquid feed or dry feed on either a restricted or an ad libitum basis, and whether their growth performance was further influenced by the water-to-feed ratio. The study was split into two parts to enable unrestricted (trial 1; n = 64) and restricted (trial 2; n = 48) feeding to be compared. Male pigs were randomly allocated to six dietary treatment groups. A standard dry pellets diet (D) was offered either as: (i) unrestricted ration (UR); (ii) restricted ration (R); or D soaked in water at a feed-to-water ratio of (iii) 1 : 1.5 restricted (1 : 1.5 R); (iv) 1 : 3 unrestricted (1 : 3 UR); (v) 1 : 3 restricted (1 : 3 R); or (vi) 1 : 3 restricted with the addition of lactic acid to adjust the feed to pH 4 (1 : 3(4) R). Liquid feeding improved (P < 0.05) average daily live-weight gain (ADG) and lean tissue growth rate (LTGR) in the 1 : 3 UR compared with DUR but did not alter feed conversion ratio (FCR). Within the R groups, ADG were greater in all of the 1 : 3 diets, whereas feed intake, and hence FCR, was lower (P < 0.001) in these groups when offered the R ration. In conclusion, liquid feeding has a beneficial influence on the performance of modern porcine genotypes during the growth/finishing phase and this is further modulated by the water-to-feed ratio.     

Effect of Chromium Picolinate Supplementation on Growth Performance and Meat Characteristics of Swine

The purpose of this study was to evaluate the effect of supplemental chromium (Cr) in the form of chromium picolinate (CrPic) on swine growth performance, meat quality, and protein deposition in skeletal muscle. Forty-eight piglets were divided into three groups randomly, fed with three different dietary levels of Cr (common basal feedstuff supplemented with a dose of 1.61 μg/g or 3.22 μg/g CrPic, which corresponded to 0.2 and 0.4 μg/g Cr). Results indicated that during the growing period (1–35 days), pigs fed with the diet supplemented with CrPic showed no improvement in body mass, average daily gain (ADG), feed consumption, or feed conversion rate (FCR) (P?>?0.05). During the finishing period, a supplementary dose of 0.2 μg Cr/g improved daily weight gain significantly (P?<?0.05), while the situation had no significance with 0.4 μg Cr/g (P?>?0.05) supplemented. For the entire growing-finishing period, body mass increased by 3.86%, ADG rose by 6.08%, and the FCR decreased by 3.30%; levels of total muscular pigment and that in the ribeye areas significantly improved (P?<?0.05) when supplementation with 0.2 μg Cr/g (P?<?0.05) was employed. However, there were no significant changes when supplemented with 0.4 μg Cr/g. While there were no changes in yield of carcass, back fat, water holding capacity, or levels of muscular crude protein and fat (P?>?0.05) in treatment, the ratio of fat-lean and RNA/DNA increased significantly supplemented with 0.2 μg Cr/g (P?<?0.05), but there were no significance with 0.4 μg Cr/g supplementation. In addition, the muscular levels of cholesterol had slightly decreased and the content of DNA in skeletal muscle showed no marked changes with 0.2 or 0.4 μg/g Cr supplementation. In conclusion, the present results suggested that dietary Cr supplementation in the dose of 0.2 μg/g could promote the growth performance, carcass characteristics, and protein deposition.     

Dietary Glutamate Supplementation Ameliorates Mycotoxin-Induced Abnormalities in the Intestinal Structure and Expression of Amino Acid Transporters in Young Pigs

The purpose of this study was to investigate the hypothesis that dietary supplementation with glutamic acid has beneficial effects on growth performance, antioxidant system, intestinal morphology, serum amino acid profile and the gene expression of intestinal amino acid transporters in growing swine fed mold-contaminated feed. Fifteen pigs (Landrace×Large White) with a mean body weight (BW) of 55 kg were randomly divided into control group (basal feed), mycotoxin group (contaminated feed) and glutamate group (2% glutamate+contaminated feed). Compared with control group, mold-contaminated feed decreased average daily gain (ADG) and increased feed conversion rate (FCR). Meanwhile, fed mold-contaminated feed impaired anti-oxidative system and intestinal morphology, as well as modified the serum amino acid profile in growing pigs. However, supplementation with glutamate exhibited potential positive effects on growth performance of pigs fed mold-contaminated feed, ameliorated the imbalance antioxidant system and abnormalities of intestinal structure caused by mycotoxins. In addition, dietary glutamate supplementation to some extent restored changed serum amino acid profile caused by mold-contaminated feed. In conclusion, glutamic acid may be act as a nutritional regulating factor to ameliorate the adverse effects induced by mycotoxins.