152 Influence of dietary vitamin concentrations and of 25(OH)D₃ in diets for growing-finishing pigs

Abstract

An experiment was conducted to test the hypothesis that the use of a high dose of a vitamin premix (above NRC requirements), combined with the addition of 25(OH)D₃, may improve productivity, decrease the incidence of osteochondrosis (OC), and improve pork quality in growing-finishing pigs. A total of 440 pigs (initial body weight: 25.5 ± 2.84 kg) were housed in 44 pens (10 pigs/pen) with 11 pens per treatment. Pigs were randomized by weight, sex, and litter of origin and allotted to a randomized complete block design with a factorial arrangement of two doses of a vitamin premix (0.125 or 0.500 kg/ton; Table 1) and two doses of 25(OH)D₃ (i.e., 0 or 50 µg/kg). The feeding program included 4 phases each lasting 21 days. Average daily gain (ADG), average daily feed intake (ADFI), gain to feed (G:F), pork quality, and histopathological evaluation of OC lesions in pigs were determined. Data were analyzed by SAS (SAS Inst. Inc., Cary, NC, USA). PROC UNIVARIATE was used to identify outliers and PROC MEANS was used to calculate mean and standard deviation for the measured variables, whereas PROC GLM was used to analyze differences among treatments. For histopathological and macroscopic evaluations of the joints, a non-parametric test using the Kruskal-Wallis method was conducted to compare groups without assuming a normal distribution. Results indicated that there were no differences in ADG, ADFI, or G:F among treatments (Table 2). However, drip loss and compression water loss were reduced (P < 0.05) in carcasses from pigs fed the greater vitamin level and 25(OH)D₃. The incidence of OC lesions was less (P < 0.01) in pigs fed the greater vitamin levels and 25(OH)D₃. In conclusion, supplementing pig diets with 25(OH)D₃ or increased vitamin levels does not enhance productive performance, but reduces the incidence of OC lesions and improves pork quality.