Anticoccidial, glycine and glutamine/glutamic acid use on diets with different threonine/lysine ratios for broiler chickens raised under health challenge / Uso de anticoccidiano, de glicina e de glutamina/ácido glutâmico em dietas com diferentes relações treonina /lisina para frangos de corte criados sob desafio sanitário

Lidson Ramos Nery

Two experiments with 4680 Cobb male broiler chickens were accomplished in order to evaluate different digestible threonine/digestible lysine ratios in rations with or without anticoccidial, glycine and glutamine/glutamic acid. In the first experiment three digestible threonine/ digestible lysine ratios were evaluated in rations supplemented or not with anticoccidial for broiler chickens under health challenge. 1800 Cobb male animals were distributed in a randomized block design with 3 x 2 factorial arrangement and three digestible threonine/ digestible lysine ratios (60, 65 and 70%) with or without anticoccidial supplementation (66 ppm salinomycin) with 12 replicates containing 25 animals per experimental unit. Aiming at increasing health challenge, birds were placed in boxes with reused bed and during the first weeks animals received water contaminated with avian bed. The performance of the animals was measured at 10, 21, 35 and42 days of age. At ages 28 and 39 (days) oocysts on the animals bed werecounted. Four broiler chickens per experimental unit at age 42 were slaughtered to evaluate cut yields (breast and breast fillet), carcass yields and abdominal fat deposition. Between 1 and 10 days of age digestible threonine/digestible lysine ratios of 65 and 70% promoted greater weight gain and better feedconversion. Anticoccidial supplementation did not affect the performance of animals during the period. From the 1st to the 21st day of age the digestible threonine/ digestible lysine ratios of 65 and 70% occasioned greater weight gains. Anticoccidial supplementation improved feed conversion during the previously described period. At 35 and 42 days of age the greatest weight gains and the best feed conversions wereobtained with digestible threonine/ digestible lysine ratios of 65 and 70% and also with anticoccidial supplementation in the rations. On the 42nd day the digestible threonine/digestible lysine ratios of 65 and 70% caused greater weight and carcass yield. Anticoccidial supplementation promoted higher weight for carcass and breast. Breast and breast fillet weights were significantly (p<0.05) influenced by the digestible threonine/digestible lysine ratios of 65 and 70%. Digestible threonine/digestible lysine ratio of 65% occasioned greater breast and breast fillet yield. The ration supplemented with anticoccidial occasioned higher breast fillet weight and yield at age 42. Abdominal fat deposition was not affected by the different digestible threonine/digestible lysine ratios, neither by anticoccidial supplementation. Oocyst counts at ages 28 and 39 days were not affected by the digestible threonine/digestible lysine ratios used. Anticoccidial supplementation promoted different (p<0.05) oocyst count at age 39 resulting in approximately 49% decrease when compared to rations without supplementation. In the second experiment three digestible threonine/digestible lysine ratios were evaluated in rations supplemented or not with glycine and glutamine/glutamic acid for broiler chickens under health challenge. 2880 Cobb male broiler chickens were distributed in arandomized block design with 3 x 2 x 2 factorial arrangement and three digestiblethreonine/ digestible lysine ratios (60, 65 and 70%) with or without glycine (0.2%) and glutamine/glutamic acid (0.75%) with 10 replicates containing 24 animals perexperimental unit. In order to enhance health challenge, animals were placed in boxes with reused bed and during the first weeks they received water contaminated with avian bed. The performance of the animals was evaluated at ages 7, 21 and 35. At age 35 two animals of each experimental unit were slaughtered to evaluate cut yields (breast and breastfillet), carcass yields and abdominal fat deposition. Between ages 1 and 7 none ofthe evaluated parameters were affected by digestible threonine/ digestible lysine ratios, neither by the supplementation with glutamine/glutamic acid mix. Glycine supplementation occasioned greater weight gain from the 1st to the 7th day and from the 1st to 21st day. The bestfeed conversion was obtained in the period between ages 1 and 21 with the digestible threonine/digestible lysine ratio of 65%. Glycine and glutamine/glutamic acid supplementation promoted better feed conversions within the same period. Digestible threonine/digestible lysine ratio of 60% caused higher ration consumption from the 1st to the 35th day. Glycine supplementation occasioned greater weight gain at age 35. Glutamine/glutamic acid supplementation promoted lower ration consumption and better feed conversion from day 1 to 35. The homogeneity of the birds was not altered by the studied variables. Carcass weight and yield at age 35 were not affected by glycine and glutamine/glutamic acid supplementation. The greatest carcass yield was obtained with digestible threonine/digestible lysine ratio of 70%. Breast weight was not altered by glycine and glutamine/glutamic acid supplementation. Digestible threonine/digestible lysine ratio of 70% promoted higher breast weight and yield. Glycine supplementation occasioned greater breast fillet weight and yield. Digestible threonine/digestible lysine ratios of 65 and 70% resulted in higher breast fillet weight and yield. Abdominal fat deposition was not affected by the different digestible threonine/digestible lysine ratios, neither by glycine and glutamine/glutamic acid. It can be concluded that the ration containing digestible threonine/digestible lysine ratio of 65% improved the parameters of performance of broiler chickens raised under health challenge between1 and 42 days of age. Oocysts count was not affected by the different studied digestible threonine/digestible lysine ratios. Anticoccidial used in the ration promoted benefic effect on the performance of birds and decreased oocysts eliminated by them. The ration containing digestible threonine/digestible lysine ratio of 65%, supplemented with 0.2% glycine and 0.75% glutamine/glutamic acid improved the performance of male broiler chickens from 1 to 35 days of age when raised under health challenge. For the same period and under the same environmental conditions, the utilization of rations containing digestible threonine/digestible lysine ratio of 70% is suggested to obtain better results concerning broiler chicken carcass characteristics.

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