Effects of Dietary L-Glutamine or L-Glutamine Plus L-Glutamic Acid Supplementation Programs on the Performance and Breast Meat Yield Uniformity of 42-d-Old Broilers

ABSTRACT

This study aimed at evaluating four dietary L-Glutamine (L-Gln) or L-Gln plus L-Glutamate (L-Glu) supplementation programs on the performance, breast yield, and uniformity of broilers. A total of 2,112 one-d-old male Cobb 500(r) broilers were distributed according to a randomized block design in a 2 × 4 factorial arrangement (L-Gln or L-Gln plus L-Glu × 4 supplementation programs), totaling eight treatments with 12 replicates of 22 broilers each. The supplementation programs consisted of the dietary inclusion or not of 0.4% of L-Gln or L-Gln plus L-Glu for four different periods 0 days (negative control), 9d, 21d, and 42d. Feed intake (FI, g), body weight gain (BWG, g), feed conversion ratio (FCR, kg/kg), coefficient of variation of body weight (CV, %), body weight uniformity (UNIF, %), breast weight (BW, g), breast yield (BY, %), coefficient of variation of breast weight (CVB), breast uniformity (UNIFB), coefficient of variation of breast yield (CVBY), and breast yield uniformity (UNIFBY) were evaluated. Birds fed the diets treatments supplemented with L-Gln or L-Gln plus L-Glu for 9d presented 3% higher BWG (p<0.05) compared with the controls. The L-Gln or L-Gln plus L-Glu supplementation until broilers were 21 days old resulted in 14, 10, 16, and 12% improvements (p<0.05) in CV, UNIF, CVBY, UNIFBY, respectively. The supplementation of 0.4% L-Gln (L-Gln 99%) or L-Gln plus L-Glu (minimum 95%) to pre-starter and starter broiler diets is recommended to improve body weight gain and uniformity.