Relações energia: proteína e substituição isoenergética dos macroingredientes da dieta de codornas europeias criadas em ambientes de conforto e de estresse pelo calor

Abstract

The objective of this study was to evaluate the substitution of soybean oil (OLS) or isolated soy protein (PIS), as energy sources of carbohydrates, lipids and proteins in low energy (E) diets, respectively: protein (P) (108 kcal E: 1% P or 2950 kcal EMAn: 27.3% PB), control (128 kcal E: 1% P or 2950 kcal EMAn: 23% PB) or high E: P (128 kcal E: 1% P or 2950 kcal EMAn: 23.0% CP) in the diet of European quails from 10 to 35 days of age. age in room temperature thermoneutral (26 ° C) or hot (35 ° C). A total of 588 quails were used, half in thermoneutral environment, and half in warm environment, distributed in a completely randomized design in a factorial scheme (3 x 2 +1) x 2 [(3 energy sources x 2 E: P + 1 ratio diet control) x two temperatures], resulting in fourteen treatments with seven replicates of six birds. The energy of the starch (12.46% in the diet) was replaced by the energy of the OLS (5.00% in the diet) or the energy of the PIS (12.04% in the diet) within each diet of low E: P ratio or high. For the analysis of the histology of the small intestine mucosa, four birds per treatment were used, and samples of approximately 1 cm of the middle portion of the duodenum, jejunum and ileum of each bird were collected, the variables analyzed were villi height, depth of crypt, relationship villus: crypt and absorption area. Data were analyzed by Duncan's test (P≤0.05). The addition of starch and OLS in the diet improved (P≤0.05) feed intake, weight gain and feed conversion compared to the addition of PIS, respectively. The low E: P ratio positively influenced weight gain and feed conversion, when compared to the high E: P ratio (P≤0.05). Quails housed at moderate temperature had better feed intake and weight gain, but feed conversion was worse compared to quails housed at elevated temperature (P≤0.05). There were interactions (P≤0.05) between the energy source and the E: P ratio. The high E: P ratio decreased feed intake and weight gain when the diet contained PIS (P≤0.05). The low E: P ratio reduced feed intake, but improved weight gain and feed conversion when OLS replaced starch in the diet (P≤0.05). The replacement of starch by PIS increased feed intake and improved feed conversion (P≤0.05). The replacement of starch by OLS or PIS did not improve the performance of quails housed at hot temperature. Quails fed diets with low E: P ratio (108: 1 - 27.3% CP and 2,950 EMAn) with corn starch or OLS have better weight gain and feed conversion than quails fed with isolated soy protein as a source of energy. The control diet positively influenced the feed conversion when compared to the high E: P diets containing starch, OLS and PIS. Soya protein isolates as a source of energy and temperature of 35 ° C have a negative impact on the performance of quails. The replacement of starch by soybean oil attenuates the negative effect of high temperature on quail weight gain. The ratio of 128/1% or 23% of protein increases the area of absorption of the duodenum region in thermal comfort and the jejunum and ileum segments in thermal stress.