Supplementing functional amino acids and polyphenols at low dose can restore performance and amino acid digestibility in broilers challenged with coccidiosis

Abstract

In broiler chickens, commercial intensive practices exacerbate the pressure of gut heath challenges such as coccidiosis. Coccidiosis impairs nutrient digestion, performance, livability of broiler chickens and reduces overall farm profitability. Literature reports that functional amino acids (AA; arginine, threonine, glutamine) and polyphenols could exert beneficial effects in broilers facing this challenge. The current study aimed at evaluating the efficiency of the supplementation of arginine, threonine and glutamine together with grape extract polyphenols (MIX) on performance, AA digestibility and gut morphology in broiler chickens challenged with coccidiosis.Two hundred eighty-eight (288) newly hatched male broiler chicks of commercial strain (Ross 308) were allocated to 3 treatments with 8 replications. For all except one treatment (Uninfected Untreated Control – UUC), birds were artificially challenged with ADVENT® coccidiosis vaccine 10x dose on day 14. Broiler chickens from the two challenged groups received either no supplementation (Infected Untreated Control – IUC) or a mix of arginine, threonine and glutamine together with grape extract polyphenols at a dose of 1 kg/Ton (IUC+MIX) from day 0 to day 35. Performance and livability were followed during the 35 days of the trial. Lesion scoring, duodenum morphology and fecal oocyst count were assessed on day 21. On day 25 nutrient digestibility was measured on a subset of birds. All data were subjected to an ANOVA and differences among means were detected by multiple range tests.During the course of the trial, coccidiosis challenge reduced growth (-3 g/d, P = 0.008) and feed conversion ratio (-3 pts, P = 0.013) without altering feed intake. It also increased total and species related lesion scores and oocyst counts in feces at d 21 (P < 0.0001). The supplementation of the additive mix restored performance to the same level as the UUC treatment but had no effect on lesion scores and fecal oocyst count. Interestingly, the coccidiosis challenge reduced villous height in duodenum (P = 0.016) which translated into lower digestibility of all AA (P < 0.05), except phenylalanine. The addition of the mix mitigated partially the effect of the challenge on digestibility and to a lesser extent on gut morphology. This study reports that the supplementation of a selected combination of functional amino acids and grape extract polyphenols can fully restore performance of coccidiosis-challenged birds with an improvement of AA digestibility. The results of this study suggest that the mode of action of the mix does not rely on a direct effect on lesion scores, oocyst count or gut morphology and still needs to be determined.