Growth curves, body nutrients deposition and determination of protein requirement for light and semi heavy hen pullets

Growth curves of pullets were adjusted to describe the deposition rates of body components and estimate the requirements in protein. Altogether 1500 poultry were randomly distributed in 30 repetitions of 25 birds. The experimental period was divided into four stages (1 to 4 weeks 5 to 11 weeks and 12 to 16 weeks old). The rations formulated based on corn and soybean meal were offered the will. Weekly, pullets were heavy and two birds separates by lineage to be in determining chemical composition of body nutrients. The informations was used to obtain the parameters of the Gompertz model. Allometric relationships were used to describe the changes in body composition in protein, lipid, ash and water in the body gutted and without feathers. The data of body weight growth of the strains pullets Dekalb White and Bovans Goldlina fit to the Gompertz function. The allometric coefficients of fat, water and mineral matter on the basis in proteic weight of the lines Dekalb and Bovans lines were respectively: 0.114 vs 1.160; 0.811 vs 0.429; 0.930 vs 0.189. There are differences among genotypes for growth rates and deposition of body nutrients and fearther. The light-line is earlier. The total protein requirements (maintenance and gain) for pullets of 1 to 4, 5 to 11 and 12 to 16 weeks of age were respectively 4,41; 9,814; 12,612 g / d for Dekalb White and 4.82; 8,859; 7,673g / d to Bovans Goldline. The aim of this work was to determine growth curves and body nutrients deposition by using Gompertz equation, and to estimate protein requirement in light and semi heavy hen pullets. In total, 1,500 hen pullets were distributed at random into 30 repetitions of 25 birds each. Experimental period was divided into three steps (1st to 4th, 5th to 11th and 12th to 16th weeks of age). Rations were formulated based on corn and soybean meal and offered ad libitum. Birds were weighed weekly. Two birds per repetition were used to determine chemical body composition and data were used to obtain Gompertz model parameters. Allometric ratios were used to describe changes in the body composition in protein, lipid, mineral matter and water in the eviscerated and featherless body. Weight-age data of Dekalb White and Bovans Goldline pullets were well described by Gompertz function. Allometric coefficients of fat, water and mineral matter in function of the protein body weight were, respectively: 0.114, 0.811 and 0.930 for Dekalb line and 1.160, 0.429 and 0.189 for Bovans line. There are differences between lines for growth rates and body nutrients and feathers deposition, with Dekalb line being the most precocious. Total protein requirements (maintenance and growth) for pullets from 1st to 4th, 5th to 11th and 12th to 16th weeks of age were 4.41; 9.814 and 12.612 g˙d-1 for Dekalb White and 4.82; 8.859 and 7.673 g˙d-1 for Bovans Goldline, respectively

High Incubation Temperature and Threonine Dietary Level Improve Ileum Response Against Post-Hatch <i>Salmonella</i> Enteritidis Inoculation in Broiler Chicks

<div><p>This study assessed the effect of both embryonic thermal manipulation and dietary threonine level on the response of broilers inoculated with <i>Salmonella</i> Enteritidis, considering bacterial counts in the cecal contents, intestinal morphology, mucin and heat shock protein 70 gene expression, body weight and weight gain. Thermal manipulation was used from 11 days of incubation until hatch, defining three treatments: standard (37.7°C), continuous high temperature (38.7°C) and continuous low temperature (36.7°C). After hatch, chicks were distributed according to a 3x2+1 factorial arrangement (three temperatures and two threonine levels and one sham-inoculated control). At two days of age, all chicks were inoculated with <i>Salmonella</i> Enteritidis, except for the sham-inoculated control group. There was no interaction between the factors on any analyses. High temperature during incubation was able to reduce colonization by <i>Salmonella</i> Enteritidis in the first days, reducing both <i>Salmonella</i> counts and the number of positive birds. It also increased mucin expression and decreased Hsp70 expression compared with other inoculated groups. High temperature during incubation and high threonine level act independently to reduce the negative effects associated to <i>Salmonella</i> Enteritidis infection on intestinal morphology and performance, with results similar to sham-inoculated birds. The findings open new perspectives for practical strategies towards the pre-harvest <i>Salmonella</i> control in the poultry industry.</p></div

Ileum heat shock protein 70 kDA (Hsp70) mRNA of chicks at 10 days of age (n = 3 per treatment).

<p>Changes in Hsp70 mRNA expression are normalized to β-actin mRNA and expressed relative to the reference gene. Means followed by the same small letter are similar by Tukey’s test. Means followed by the same capital letter are similar to the sham-inoculated treatment (Control) by Dunnet’s test (5%). SE-inoculated, inoculated with <i>Salmonella</i> Enteritidis at 2 days of age; sham-inoculated, inoculated with nutrient broth at 2d. (A) Effect of thermal manipulation during incubation. (B) Effect of post-hatch threonine dietary levels.</p