Effect of Light/Dark Cycle on Amino Acids and Protein in the Muscle of Chicken

Poultry meat quality is affected by numerous factors. However, light schedule for rearing poultry birds is considered the most important factor for productions and meat quality. In the present study L:D 04:04, L:D 16:08, L:D 12:12 and LL conditions was utilized for rearing the birds. Water was provided ad libitum. Care was taken to prevent light entering the cage from outside. From each group nine birds were decapitated and tissues were obtained on 1^st, 14^th, 28^th and 42^nd days. The Tissues were stored at -20°C and was later estimated for total muscle protein and amino acid. The mean concentration and SE of free amino acid (gm/100gm) on LD 04:04, LD 16:08, LD 12:12 and LL was found to be 0.13 ± 0.01, 0.17 ± 0.02, 0.14 ± 0.01 and 0.19 ± 0.02 respectively and that of protein was 15.22 ± 1.23, 25.98 ± 1.00, 21.42 ± 1.21 and 25.79 ± 1.45 respectively. A significantly higher concentration of free amino acid in LL schedule as compared to LD 12:12 and LD 04:04 have been observed in the present study (p<0.05). Result suggests that continuous light may be beneficial for quality poultry meat production as higher level of free amino acid has also been implicated for lowering protein breakdown (Tipton and Wolfe, 2004). However statistical analysis of the data fails to detect any difference in the level of muscle free amino acid among the birds exposed to LL and 16:08 LD schedules. Similarly difference in the protein content between these two groups of birds was also not significant. Hence the LD schedule 16:08 may be more suitable and economic for quality meet production in poultry industry especially since it requires less energy for production.