Effect of reduced dietary crude protein and supplemental limiting amino acids on the growth and carcass characteristics of Swarnadhara chicks

Abstract

A six-week trial was conducted to determine the effect of lowering dietary crude protein levels with supplementation of limiting amino acid on growth performance, and carcass characteristics in one of the Indian improved crossbred Swarnadhara chicks in a completely randomized design having five treatments and four replications of 20 birds in each. Five isocaloric (2800 ME Kcal//kg) experimental diets based on corn-soy bean meal were formulated in a gradual crude protein decline from 21 % (control T1) to 19% by 0.5% interval. The levels of limiting amino acids namely methionine, lysine, threonine and tryptophan were met as that of control (T1) by adding synthetic preparations. Highest body weight was recorded in 2% crude protein reduced group (T5) which was comparable with control (T1). However, cumulative feed intake and feed conversion ratio of different treatments were not significantly different. Moreover, carcass parameters like dressing percentage, breast meat yield, liver and heart weights remained unaffected by the dietary treatments. Relative gizzard weight and abdominal fat weights showed variations and lower dietary protein diets were comparable with control diet (T1). In summary, crude protein content of Swarnadhara chick diet can be reduced to 19% with essential AA fortification without any adverse effect on growth performance and carcass characteristics during 0-6 weeks of age.

Effect of supplementing limiting amino acids on growth performance and carcass traits of Gramasree male chicks fed with low protein diets

“…The present finding is in agreement with Shao et al (2018) and Joseph et al (2018), who assessed that reduction in dietary crude protein of birds with supplementation of essential amino acids did not affect the final body weight and weight gain. The results are also in par with the findings by Divya (2014) who experimented on Gramasree cockerels with dietary treatments having 2800 kcal/kg ME and CP ranging from 22 to 18 per cent without limiting amino acids supplementation.…”

“…The increased abdominal fat yield of birds fed with low CP diets observed in this study was experienced by many researchers previously. Raju et al (1999), Joseph et al (2018) and Karthika et al (2019) have also reported that low protein diets with amino acid supply in the diets increased the abdominal fat of the broilers.…”

“…But CP reduced from 23 to 18.5 per cent, with amino acid supplementation reported that feed consumption was lower in low CP diet groups. Shao et al (2018) reduced the CP level of broiler diet up to 17 per cent by balancing with amino acid supply whereas Joseph et al (2018) experimented on Swarnadhara chicks by reducing CP up to 19 per cent with limiting amino acid supplementation. Similar to the present study, both of them observed no significant difference among the cumulative FCR among the treatments.…”