Digestible lysine levels obtained by two methods of formulation of diets for 22-to-42-day-old broilers

Abstract

-The objective of this study was to evaluate the effect of digestible lysine levels in diets with or without supplementation of industrial amino acids on performance, carcass characteristics and nitrogen excretion in broilers of 22 to 42 days of age. Birds were distributed in a completely randomized experimental design in a 4 × 2 factorial arrangement, with four digestible lysine levels (9.0, 10.0, 11.0 and 12.0 g/kg) and two methods to obtain the lysine levels (variation in the proportion of corn and soybean meal, without supplementation; or supplementation of industrial amino acids), eight replicates and 20 birds per replicate. There was an interaction effect on the performance characteristics and on the weights and yields of prime cuts. In both diets, feed conversion improved linearly as the lysine levels were increased. Feed intake; weight gain; carcass, thigh and drumstick weights; and boneless breast yield increased and abdominal fat reduced linearly as the lysine levels were increased in the unsupplemented diet. The lysine levels of the supplemented diets linearly reduced the yield of drumstick and quadratically reduced the yields of bone-in and boneless breast up to the estimated levels of 10.4 and 10.7 g/kg, respectively. Diets without supplementation increased the excretion and retention of nitrogen. The levels of 9.0 and 12.0 g/kg digestible lysine obtained with supplementation of industrial amino acids and without it, respectively, provide the best performance and yield of prime cuts in the birds. Diets in which the digestible lysine levels are obtained without supplementation provide better performance responses and carcass characteristics compared with supplemented diets.

Effect of Protein Bound and Free Lysine on Growth Performance, Meat Quality, Blood Hematology and Economics in Broilers

“…Improved FCR was observed due to higher body weight by addition of L-Lys Sulfate. Results are in line with findings of Oliveira et al (2014) reported that FCR was significantly higher in diets with protein bound Lys as compared to diets with free Lys supplementation. According to results of present study in free Lys sources the L-Lys sulfate had higher feed conversion ratio as compared to L-Lys HCl.…”

“…This might be due to that addition of synthetic lysine reduces the high lysine ingredient proportion resulting in reduced feed intake. Results are in according with findings of Oliveira et al (2014) who showed that feed intake was significantly lower in Lys supplementation than protein bound Lys diets. Both synthetic Lys sources (L-Lys HCl and L-Lys sulfate) supplementation had similar feed intake.…”

“…As, lysine has an important role in broiler growth and a sufficient amount of lysine is required to meet that requirement (Brasil et al, 2018). Results are in line with findings of Oliveira et al (2014) reported that body weight gain was significantly higher in protein bound Lys diets as compared to diets with Lys supplementation. Both synthetic Lys sources (L-Lys HCl and L-Lys sulfate) supplementation did not show statistical difference in term of body weight gain.…”