Relações entre aminoácidos sulfurosos e colina para codornas de corte em crescimento

Abstract

Two experiments were conducted with the objective of estimating the nutritional requirements of methionine and cystine, as well as to establish the relationship between the sulfur amino acids and to determine the best level of partial substitution of digestible methionine by choline in the diets of meat-type quails (Coturnix coturnix coturnix) in the periods from 1-14 and 15-35 days old. We evaluated the performance, body chemistry composition and liver composition, organ weights and carcass parts, warping, body yield, blood parameters and bone of birds. Experiment 1 aimed to determine the nutritional requirements of digestible methionine (Metd) and digestible cysteine (Cysd), as well as establish the relationship between the sulfur amino acids in the period from 1 to 14 days (initial phase) and 15 to 35 days old (final phase growth). In the initial phase 2,400 not sexed meat-type quails were distributed in a completely randomized design (DIC), in a 4x4 factorial arrangement, with four Metd levels (0.50, 0.62, 0.74 and 0.86%) and four Cysd levels (0.40, 0.53, 0.66 and 0.79%), totaling 16 treatments with three replicates and 50 quails per experimental unit. The body weight (BW), weight gain (WG) and the accumulated body biomass (ABB) were quadratically affected in function of Metd levels (BW, P=0.010) (WG, P=0.008), (ABB, P=0.002) and Cysd (BW, P=0.080), (WG, P=0.080), (ABB, P=0.069) in the diets. Estimates for the maximum BW, WG and ABB were obtained with diets containing 0.66% of Metd and 0.59% of Cysd, 0.66% of Metd and 0.60% of Cysd and 0.66% of Metd and 0.54% Cysd, respectively. For feed conversion (FC) there was a quadratic effect (P=0.007), estimating the best FC using 0.64% Metd in the diet. It is concluded that the requirements of digestible met + cis and the relationship between Metd:Cysd for maximum weight gain of meat-type quails were 1.26% (0.66% of Metd + 0.60% of Cysd in the diet) and 52.38%, respectively. In the final phase of growth 1,680 meat-type quails raised until the beginning of the experiment in a conventional system, not sexed, The animals were distributed in a completely randomized design, in a 4x4 factorial arrangement, with four Metd levels (0.45, 0.57, 0.69 and 0.81%) and four Cysd levels (0.35, 0.48, 0.61 and 0.74%), totaling 16 treatments, with three replicates and 35 quails per experimental unit. The BW, WG and ABB were quadratically influenced in function of increased Metd levels (BW, P=0.067) (WG, P=0.069) (ABB, P=0.080) and Cysd (BW, P=0.004) (WG, P=0.002) (ABB, P=0.002) in the experimental diets. Estimates for obtaining of the maximum values of BW, WG and ABB were taken with diets containing 0.63% Metd and 0.58% Cysd. It is concluded that the requirements of digestible met + cys and the relationship between Metd: Cysd for maximum performance of meat-type quails were 1.21% (0.63% of Metd + 0.58% of Cysd/kg diet) and 52.07%, respectively. Experiment 2 aimed to determine the best level of partial substitution of Metd by choline (CHO) in diet for meat-type quails in the period from 1 to 14 days (initial phase) and of 15 to 35 days old (final phase of growth). In the initial phase 2,400 not sexed meat-type quails were distributed in a completely randomized design, in a 4x4 factorial arrangement, with four digestible methionine (Metd) levels (0.48, 0.54, 0.60 and 0.66%) and four choline levels (300, 800, 1300 and 1800 mg/kg), totaling 16 treatments with three replicates and 50 quails per experimental unit. The BW, WG, ABB and FC were linearly influenced in function of Metd levels (BW, P=0.058) (WG, P=0.050) (ABB, P=0.022) (FC, P=0.019) and CHO (BW, P=0.002) (WG, P=0,002) (ABB, P=0.012) (FC, P=0.017) in the diets. It is concluded that the requirement of Metd for maximum weight gain of meat-type quails was at least 0.66% of Metd in the diet. In the supplemented levels of CHO, it has not been possible topromote the completion of the Metd requirement. In the final phase of growth 1,680 meat-type quails raised in the conventional system until the beginning of the period experiment, not sexed. The birds were distributed in a completely randomized design, in a 4x4 factorial arrangement, with four Metd levels (0.45, 0.51, 0.57 and 0.63%) and four CHO levels (300, 800, 1300 and 1800 mg/kg), totaling 16 treatments with three replicates and 35 quails per experimental unit. The BW, WG and ABB were linearly influenced in function of increasing Metd levels (BW, P=0.014) (WG, P=0.010) (ABB, P=0.013) and CHO (BW, P=0.047) (WG, P=0.034) (ABB, P=0.030) in the experimental diets, occurring interaction between Metd levels and CHO, on BW (P=0.053), WG (P=0.039) and ABB (P=0.035). It is concluded that the requirement of Metd for maximum performance of meat-type quails was at least 0.63% of Metd in the diet. In the supplemented levels of CHO, it has not been possible to promote the completion of the Metd requirement.