Intermittent dilution of dietary digestible lysine lowers the incidence of white striping by suppressing the growth, lipid synthesis, and muscle damage in broiler chickens.

BACKGROUND: White striping (WS) is a myopathy of breast muscle (Pectoralis major) that affects the quality and consumer acceptance of breast fillets of broiler chickens. Previous studies have shown that intermittent dilution of dietary nutrients suppresses the development of WS on the breast muscle of broiler chickens. However, the mechanism by which these interventions reduce the occurrence of WS remains inconclusive. In this study, we adopted intermittent reduction of dietary digestible lysine (dLys) density or metabolizable energy (ME) and amino acid (AA) density using chemical and fatty acid composition of breast fillets, and blood metabolites to understand the mechanism while histopathology and immunohistochemistry of breast muscles were used for confirmation. RESULTS: Occurrence of WS was lower in broiler chickens fed 85% dLys diets in comparison with other groups. Crude protein and ether extract in breast meat of 85% dLys groups were greater (P < 0.001) and lower (P = 0.010), respectively. Serum concentrations of lipid metabolites and enzymes were lower in broiler chickens fed 85% dLys diets than control group (P < 0.05). Feeding 85% dLys diets had low degree of myodegeneration and necrosis, inflammation, lipid deposition, infiltration of T-lymphocyte (CD3+) and macrophages (Iba-1+), and low expression of heat-shock protein 70 (HSP70) than other groups (P < 0.001). CONCLUSION: Dilution of dietary dLys to 85% of the required quantities reduces the development of WS in broiler chickens by slowing the growth, lipid synthesis, and muscle damage confirmed by lower extent of histopathological lesions. © 2022 Society of Chemical Industry.

Effect of humate supplementation to feed and/or litter on performance, intestinal viscosity, litter quality, and occurrence of footpad dermatitis in broilers fed barley-based diets.

We investigated the effect of in-feed and/or in-litter supplemental humate against footpad dermatitis (FPD) in broilers fed diets based on barley. Three hundred and sixty 1-day-old Ross 308 broiler chickens were randomly distributed to 24 floor pens (4 treatments, each consisting of 6 replicate pens; 15 chickens per pen) as a completely randomized design with 2 × 2 factorial arrangement of two levels of supplemental humate in feed (0 and 1 g/kg feed) and litter (0 and 5 g/kg litter). Growth performance, intestinal viscosity, litter quality, and incidence and severity of FPD in broilers were measured. In addition, malondialdehyde (MDA) and superoxide dismutase (SOD) levels were determined in blood and footpad tissues of broilers with different FPD scores. The results revealed that there was no interaction between humate supplementation to feed and litter. Neither dietary nor litter supplementation of humate had a significant effect on growth performance, intestinal viscosity, litter quality, and occurrence of FPD. And also, MDA and SOD levels in serum and footpad tissue did not affect by either dietary or litter supplementation of humate. The presence of FPD (score 1) had no effect on MDA and SOD levels in serum, however, increased the MDA and SOD levels (P < 0.001, P = 0.001, respectively) in footpad tissue of broilers. The intestinal viscosity did not differ between FPD scores 0 and 1. In conclusion, findings of this experiment suggest that humate supplementation to feed and litter did not alleviate FPD development in broilers fed diets based on barley. In addition, the presence of FPD lesions increases the MDA and SOD levels in the footpad tissues.