Response of growing chicks to supplementation of low protein diets with leucine, valine and glycine-glutamic acid

Abstract

This experiment was conducted to determine the interaction effects that resulted from supplementation of low-protein diets with leucine (Leu), valine (Val), and glycine-glutamic acid (Gly-Glu) on growing broiler chicks from 11 to 24 days old. Two levels of digestible Leu (1.07 and 1.50%) and three levels of digestible Val (0.64, 0.74, and 0.84%) were investigated as a 2 × 3 factorial arrangement of treatments with 12 replicates. The diet with 1.07% digestible Leu and 0.84% digestible Val was supplemented with 0.34% Gly and 1.32% Glu as an additional treatment (T7). At 24 days old, 0.84% Val significantly improved feed conversion with 1.07% Leu, but 0.74% Val was sufficient with 1.50% Leu. The T7 diet further improved feed conversion. Increasing dietary Val from 0.64% to 0.74% significantly increased bone density and strength at the lower level of dietary Leu, while T7 significantly increased tibia breaking strength. There were significant Leu × Val interactions for villus height, crypt depth, and goblet cell numbers. Val at 0.84% maximized the development of the jejunum at the lower Leu level, while goblet cell number and crypt depth were impaired by increments of Val at the higher level of Leu. In conclusion, increasing the level of Val in low-protein grower diets significantly improved performance, bone and jejunum development of broilers, and its interaction with Leu was important. Therefore, these two amino acids (AAs) and the possibility of Gly-Glu fortification must be considered when formulating low-protein broiler diets.
 Keywords: bone traits, branched-chain amino acids, broilers, gut histology, performance

Beta‐hydroxy‐β‐methyl butyrate‐supplemented diet for broiler chickens is more conducive to dietary protein reduction than a leucine‐supplemented diet until 21 days old

“…In the present study, dietary leucine and HMB had beneficial effects on broiler performance during the finisher phase. These effects may be attributed to an appropriate ratio among BCAA of the finisher diet used and reduced valine and isoleucine requirements 8,33 . This may explain why the dietary leucine could have compromised broiler performance in our study 5,9,10 .…”

“…These effects may be attributed to an appropriate ratio among BCAA of the finisher diet used and reduced valine and isoleucine requirements. 8,33 This may explain why the dietary leucine could have compromised broiler performance in our study. 5,9,10 Also, during the starter phase, the decrease in the FI of the LLPD broilers could have induced a deficiency of isoleucine and valine as well, which is associated with growth depression.…”

Performance and immune response of broilers born to breeders of different ages and fed different valine levels

“…These amino acids are catabolized in intestinal cells and are important for intestinal nutrient absorption. Therefore, any changes in intestinal morphometric structure may affect nutrient metabolizability and performance (Adabi et al, 2019), and duodenum weight may be important in facilitating BWG in young broilers (Wijtten et al, 2010). The digestible valine levels increased villus height and V:C ratio in the jejunum only in the broilers from 52-week-old breeders, indicating that breeder age affects intestinal development in broilers in response to the diet.…”

“…The digestible valine levels increased villus height and V:C ratio in the jejunum only in the broilers from 52-week-old breeders, indicating that breeder age affects intestinal development in broilers in response to the diet. According to Adabi et al (2019), the observed improvement in the jejunum with the increasing valine levels may be attributed to the utilization of dietary valine as a precursor of nonessential amino acids in the mucosa. Branched-chain amino acids could enhance intestinal development by increasing the local glucose uptake for animals and humans, since they regulate the expression and translocation of intestinal glucose transporters through insulin-dependent or insulin-independent pathways (Zhang et al, 2017).…”

Effect of Adding L-Arginine to Broiler Diets on Physiological Performance

“…Numerous experiments and initiatives have aimed to diminish the reliance on animal protein in broiler chicken diets since the onset of the new millennium. However, some endeavors have fallen short of achieving satisfactory performance outcomes compared to conventional animal protein diets, The primary factors contributing to the suboptimal growth performance of broiler chickens can be attributed to deficiencies in non-essential amino acids and the competition among branched-chain amino acids (BCAA) [4]. Although there has been a noteworthy shift from employing Total Amino Acids (TAA) to Digestible Amino Acids (DAA) when designing poultry diets, some entities or nutritionists still formulate broiler diets based on TAA requirements.…”