The effect of vitamin E on growth performance and meat quality in broilers given diets containing distillers’ dried grain with solubles (DDGS)

Gradually Increasing Vitamin E Dose Allows Increasing Dietary Polyunsaturation Level While Maintaining the Oxidation Status of Lipids and Proteins in Chicken Breast Muscle

Feeding broilers diets high in n-3 long-chain polyunsaturated fatty acids (n-3 PUFA) increases their incorporation into the meat but it may compromise meat quality due to oxidation of lipids and protein. Increased dietary vitamin E (vE) level downregulates this process, but its excessive level might exceed the physiological requirements for the maintenance of redox balance. This study investigated the sensory characteristics and oxidative status of meat from chickens fed diets supplemented with fish oil (FO) with or without gradually increasing doses of vE. The meat samples were obtained from a total of 27 female broilers of Ross 308 strain (9 birds per each of 3 dietary treatments), which were housed according to the standard management practice for commercial chicken houses over a period of 36 days. Chickens were fed diets containing 80 g/kg of supplemental fat, but the diets differed in fat composition; control diet (80 g/kg diet beef tallow as supplemental fat and a basal vE dose); 40 IU of dl-α-tocopheryl acetate; diet containing mixture of FO and beef tallow as supplemental fat (50:30 w/w g/kg diet) and a basal vE dose (E1), or diet (E2) as diet E1 but with gradually increasing vE dose (120/240 IU/kg diet fed between days 8–21 and days 22–36, respectively). The highest sensory quality and the lowest oxidative status of meat was found in the control chickens. FO decreased the sensory quality of the meat and increased lipid oxidation as well it had an impact on the lipid profile in muscle tissue (PUFA, n-3 ALA, EPA, DHA). Administration of a graded vE dose increased the sensory quality of the meat and did not limit lipid oxidation but maintained protein oxidation balance.

Effects of different feeding regimens with protease supplementation on growth, amino acid digestibility, economic efficiency, blood biochemical parameters, and intestinal histology in broiler chickens

Background

This study was conducted to estimate the impacts of using varied feeding regimens with or without protease supplementation on the growth performance, apparent amino acid ileal digestibility (AID%), economic efficiency, intestinal histology, and blood biochemical parameters of broiler chickens. Three hundred one-day-old chicks (Ross 308 broiler) were randomly allotted to a 3 × 2 factorial design. The experimental design consisted of three feeding regimens; FR1: a recommended protein SBM diet, FR2: a low-protein SBM diet, and FR3: a low-protein diet with the inclusion of 5% DDGS and 5% SFM, with or without protease supplementation (250 mg/kg).

Results

Increased feed intake and feed conversion ratio were observed in the FR3 treatment during the starter stage and decreased body weight and body weight gain during the grower stage. However, there was no significant effect of the different feeding regimens, protease supplementation, or interaction on the overall performance. The economic value of diets also remained unaffected by the different feeding regimens, protease supplementation, or interaction. Protease supplementation resulted in lowering the AID% of tryptophan and leucine. Reduced AID% of methionine was evident in the FR2 + VE and FR3 − VE treatments. Histological findings substantiated the FR3 treatment mediated a decrease in the duodenal and jejunal villous height (VH), jejunal villous width (VW), and ileal VW, whereas, increase in the ileal crypt depth (CD). The FR2 + VE treatment reduced the VH:CD ratio in the duodenum. The duodenal CD and the jejunal goblet cell count were reduced as a consequence of protease supplementation. The FR3 + VE treatment documented a rise in duodenal CD, while an increase in the jejunal goblet cell count was observed in the FR3 − VE treatment. The FR3 treatment enhanced the IgM serum levels compared to the FR1 and FR2 treatments. IgM serum levels were also elevated following protease supplementation. FR3 + VE treatment increased IgM serum levels. The highest serum ALP was found in the FR3 treatment, whereas the lowest level was obtained in the FR2 treatment.

Conclusion

Low-protein SBM-based diets could be used without affecting the birds’ growth. Altered morphometric measures of the intestine and increased IgM and ALP levels indicated the low-protein SBM/DDGS-SFM diet-induced damage of the intestinal histoarchitecture and immune system of birds. These different diets and protease supplementation failed to affect economic efficiency positively.

Three indel variants in chicken LPIN1 exon 6/flanking region are associated with performance and carcass traits

LPIN1 is a Mg(2+)-dependent phosphatidic acid phosphatase. Variation in chicken LPIN1 exon 6 and its flanking regions were identified and three indel variants in 6 breeds and their associations with performance traits were studied. Seven variants were detected from 6 breeds, which contained a synonymous tri-allelic variant (c.924A/T/C) and three indels. The exon 6 variants detected from chicken breeds were conserved among bird species. The indel variation frequency presented clear differences among breeds. Two coding indels (c.1014-1018del3 and c.1125-1138del12) were multiples of three nucleotides and maintained the open reading frames of LPIN1 proteins. However, they were predicted to result in the clear change of the RNA secondary structure of chicken LPIN1 exon 6 and LPIN1 protein conformation. The association analysis showed that c.871-15-22del6 variation had a significant effect on body weight at hatch (BW0) and 2 weeks (BW2); c. 1014-1018del3 variation had a significant effect on BW4, BW6, caecum length and gizzard weight (GW) traits; c.1125-1138del12 variation had a significant effect on BW12, shank length at 4 weeks (SL4), carcass weight, lactate dehydrogenase traits (LDH), glucose (GLU) and albumin (ALB) traits. The genotype combination for c.1014-1018del3 and c.1125-1138del12 also presented significant effects on SL4, SL8, GW, leg muscle weight, ALB, GLU and LDH. The study demonstrated that chicken LPIN1 has an important effect on body, carcass and organ weight, serum LDH, GLU and ALB level.

Carcass and meat quality traits of chickens fed diets concurrently supplemented with vitamins C and E under constant heat stress

The objective of this study was to determine if a diet supplemented simultaneously with vitamins C and E would alleviate the negative effects of heat stress, applied between 28 and 42 days of age, on performance, carcass and meat quality traits of broiler chickens. A total of 384 male broiler chickens were assigned to a completely randomized design, with a 2×3 factorial arrangement (diet with or without vitamin supplementation and two ambient temperatures plus a pair-feeding group) and 16 replicates. Chickens were kept in thermoneutral conditions up to 28 days of age. They were then housed in groups of four per cage, in three environmentally controlled chambers: two thermoneutral (22.5 and 22.6°C) and one for heat stress (32°C). Half the chickens were fed a diet supplemented with vitamins C (257 to 288 mg/kg) and E (93 to 109 mg/kg). In the thermoneutral chambers, half of the chickens were pair-fed to heat stressed chickens, receiving each day the average feed intake recorded in the heat stress chamber in the previous day. Meat physical quality analyses were performed on the pectoralis major muscle. No ambient temperature×diet supplementation interaction effects were detected on performance, carcass, or meat quality traits. The supplemented diet resulted in lower growth performance, attributed either to a carry-over effect of the lower initial BW, or to a possible catabolic effect of vitamins C and E when supplemented simultaneously at high levels. Heat stress reduced slaughter and carcass weights, average daily gain and feed intake, and increased feed conversion. Growth performance of pair-fed chickens was similar to that of heat stressed chickens. Exposure to heat stress increased carcass and abdominal fat percentages, but reduced breast, liver and heart percentages. Pair-fed chickens showed the lowest fat percentage and their breast percentage was similar to controls. Heat stress increased meat pH and negatively affected meat color and cooking loss. In pair-fed chickens, meat color was similar to the heat stressed group. Shear force was not influenced by heat stress, but pair-fed chickens showed the tenderest meat. In conclusion, reduction in growth performance and negative changes in meat color in heat stressed chickens were attributed to depression in feed intake, whereas negative changes in body composition, higher meat pH and cooking loss were credited to high ambient temperature per se. Diet supplementation with vitamins C and E as antioxidants did not mitigate any of these negative effects.

The effects of conjugated linoleic acid on growth performance, carcass traits, meat quality, antioxidant capacity, and fatty acid composition of broilers fed corn dried distillers grains with solubles

This study investigated the effects of dietary supplementation with conjugated linoleic acid (CLA) on the growth performance, carcass traits, meat quality, antioxidant capacity, and fatty acid composition of broilers fed corn dried distillers grains with solubles (DDGS). Four hundred eighty 1-d-old broilers were randomly assigned to 4 groups, consisting of 6 replicates with 20 broilers each. Broilers were allocated 1 of 4 diets and fed for 49 d in a 2 × 2 factorial design. The dietary treatments consisted of 2 levels of DDGS (0 or 15%) and 2 levels of CLA (0 or 1%). The results of growth performance analyses showed that dietary supplementation with 1% CLA, 15% DDGS, or both in broilers had no significant effects on ADG, ADFI, and feed/gain (P > 0.05). Dietary supplementation with 15% DDGS did not significantly affect meat color values, drip loss percentage, pH value at 15 min, crude fat content, or shear force value (P > 0.05). Diets supplemented with 15% DDGS decreased the proportions of saturated fatty acids (P < 0.05) and monounsaturated fatty acids but increased the proportion of polyunsaturated fatty acids of the thigh meat (P < 0.05). Diets supplemented with 1% CLA significantly decreased the abdominal fat percentage (P < 0.05). Supplementation with 1% CLA increased the crude fat content and decreased the color (b*) value and shear force value of the breast meat (P < 0.05). Diets supplemented with 1% CLA increased the total superoxide dismutase activity of the serum, breast meat, and liver, and decreased the malondialdehyde content of the serum and breast meat (P < 0.05). Supplementation with 1% CLA decreased the proportion of monounsaturated fatty acids and increased the proportion of saturated fatty acids (P < 0.05). Accumulation of CLA in the thigh meat was significantly increased (P < 0.05) with increasing CLA level in the diet. In conclusion, dietary supplementation with 1% CLA had positive effects on meat quality, antioxidant capacity, and fatty acid composition of broilers, although it had no significant effect on growth performance.

Detection of exonic variants within the melanocortin 1 receptor (MC1R) gene in Black Silky, White Leghorn and Golden duckwing Araucana chicken

The melanocortin 1 receptor (MC1R) gene can be considered a candidate functional gene for the pigmentation of plumage color. The aim of this study was to investigate the association between the genotype frequencies of g.69 T>C, g.376 G>A and g.427 A>G SNPs within the MC1R gene in Black silky (O), Golden duckwing Araucana (GA) and White Leghorn (W). The CC and AA genotype frequencies of g.69 T>C and g.427 A>G SNPs in White Leghorn (W) were both 1.000, and the TT genotype frequency of the g.69 T>C SNP in Golden duckwing Araucana (GA) was also 1.000. The GG and AA genotype frequencies of g.376 G>A and g.427 A>G SNPs in Black silky (O) were both 0.100. When a haplotype is observed using a combination of markers, a Golden duckwing Araucana (GA) can especially be distinguished when it is a TAG, TGG and TAA type in the SNP combination of the MC1R gene. In case of the CAA types, only White Leghorn (W) could specifically be distinguished. Therefore, three SNPs in MC1R may provide identification in chicken breeds.