Efeito da substituição da silagem de grãos de milho reconstituídos pela polpa cítrica em dietas para cordeiros

Abstract

The aim was to evaluate the inclusion of citrus pulp as an energy source in the diet of lambs. Thus, an experiment was conducted at the Animal Science Department of the Faculty of Agricultural Sciences at UFGD, using 12 whole-breed lambs (44.25 ± 8 kg of initial body weight, 7 ± 0.5 months of age), distributed in a 3x3 Latin square experimental design, comprising periods of 14 days of adaptation and five days of data collection. The treatments evaluated were: 1) Control diet: main energy source of reconstituted corn grain silage, without the addition of pelleted citrus pulp; 2) Diet 50: inclusion of 30% citrus pulp in the total dry matter (MS) of the diet, replacing the reconstituted corn grain silage (SGMR) by 50% and 3) Diet 100: inclusion of 54% citrus pulp in the Total DM of the diet, replacing the SGMR by 100%. The animals were housed in metabolic cages, and the consumption and digestibility of dry matter and nutrients, as well as rumen fermentation, nitrogen balance and microbial protein synthesis were evaluated. The replacement of reconstituted corn grain silage (SGMR) by citrus pulp (PC) caused a quadratic effect (p <0.05) on dry matter consumption (MS) observing an increase in consumption when the 27% level was included in the MS (from 1.37 kg/day of MS in the control treatment to 1.41 kg/day) and presenting a decrease in the level of total silage replacement (diet 100 with 54% of PC in MS 1.28 kg / day). The FDN digestibility coefficient increased linearly with the inclusion of citrus pulp, the control diet showed 69.40%, the diet with 27% PC in MS showed 72.37% and the diet with 54% PC in MS showed 75.55%. The three diets offered to the lambs did not cause a difference in the N-consumed, however, the loss of nitrogen in the feces was greater for the diets with citrus pulp compared to the control, while the loss of nitrogen in the urine was greater for the control diet (18.68g/day). The efficiency in the microbial protein synthesis was higher for the diets containing the citrus pulp, observed by the linear increase of the N-microbial and PB-microbial (74.44 g/day of microbial protein in the control diet to 98.17g/day in the diet with 27% PC in MS and to 105.33 g/day in the diet with 54% PC in MS). It is also possible to observe the linear increase in ruminal pH (5.72; 5.92 and 3.32) as the substitution of silage for the co-product increases. It was concluded that the co product can be used in association or substitution to corn grain silage reconstituted in the lambs diet.