Mexilhão dourado (Limnoperna fortunei) na alimentação de frangos de corte utilizando tanino como sequestrante de metais pesados

Abstract

The present work aimed to evaluate the use of tannins as adsorbent of heavy metals in broiler chicks fed diets with different levels of mussel flour inclusion in replacement of limestone of the feeding. Two experiments were divided in two phases with two assays each. In the first experiment we conducted a trial to evaluate the performance of broiler chicks from 1 to 21 days fed wattle tannin, using for it 720 Cobb-500 1-day-old male broiler chicks distributed in a completely randomized design with six treatments and six replicates of 20 birds in each experimental unit. The treatments were composed by basal diets with increasing levels of wattle tannin (0, 250, 500, 750, 1000, 1250 g/ton-1 of wattle tannin). The results showed that the use of 250 g/ton-1 of tannin was detrimental to performance, and morphometric measurements suffered no statistical difference using tannin in the diet. In the second trial, we evaluated the performance of broiler chicks from 1 to 21 days of age fed increasing levels (0, 25, 50, 75, 100%) of replacement of mussel meal by limestone in feeding and still supplementation or not of wattle tannin (250 g/ton-1 of wattle tannin) with 5 replicates per treatment. For that, 1200 Cobb-500 1-day-old male broiler chicks were housed in a completely randomized design, with 24 birds each. The results showed that the golden mussel has lot of calcium, low levels of heavy metals, and microbiological contamination did not present or is below the amounts allowed by law. For performance, the data demonstrated that the use of mussel can be performed up to 100% replacement of the limestone in feeding without affecting the variables, but the use of 250 g/ton-1 of wattle tannin was detrimental to the performance of broiler chicks. There was no influence on the use of mussel and tannin on the deposition of heavy metals in the body of birds. The variables, liver and kidneys showed the interaction between the tested diets. The bony features, just gray on fresh matter showed interaction between treatments. In the second experiment, the first test was to evaluate the performance of broiler chickens to the stage 21-42 days, fed with wattle tannin. For that, 648 Cobb-500 21-days-old male broilers were distributed in a completely randomized design, divided into six treatments and six replicates of 18 birds in each experimental unit. The treatments were composed by basal diets with increasing levels of wattle tannin (0, 250, 500, 750, 1000, 1250 g/ton-1 of wattle tannin). The data showed that the use of levels above 500 g / t of wattle tannin in the diet is detrimental to the performance of the birds, and there were no statistical differences in morphometric measures. Carcass yield decreased linearly with the addition of tannin in the diet and there was a decrease in fat deposition, and an increase in liver size. In the second trial, the performance of broilers from 21 to 42 days was evaluated. For that, 900 Cobb-500 21-days-old male broilers were housed in a completely randomized design, with increasing levels of substitution (0, 25, 50, 75, 100%) of the golden mussel flour in replacement of limestone and also with supplement or not of wattle tannin (250 g/ton-1 of wattle tannin) with 5 replicates per treatment and 18 birds in each experimental unit. The performance showed that the use of mussel can be performed up to 100% in replacement of the limestone in the feeding without affecting the variables, but the use of 250 g/ton-1 of wattle tannin was detrimental to the performance of broiler chickens cutting. For bony features, the use of tannin decreased bone strength (kgf) and increased phosphorus in natural matter, and there was an interaction between variables to Seedor index and gray on fresh matter. The use of tannin negatively affected carcass yield and the relative weight of kidneys, and there was a significant interaction for yield wings and legs. Calcium levels in the blood suffered interaction between the substitution levels studied