Uso da 1,25-dihidroxicolecalciferol glicosídeo na substituição parcial ou total do colecalciferol na alimentação de leitões

Abstract

The objective of this work was to evaluate the effect of cholecalciferol (vitamin D3) and 1,25-dihydroxycholecalciferol glycoside (1,25(OH)2D3) on the feed of piglets in the nursery phase. Two experiments were carried out, digestibility experiment, using 36 male piglets with an average weight of 18,79 ± 3,37 kg, distributed in a block design, with four treatments, nine repetitions and one animal per experimental unit (EU). The procedures consisted of: D3 = 1969 IU of cholecalciferol; Negative control (NC) = vitamin D-free diet; 50% = 984,5 IU cholecalciferol + 0,375 µg 1,25(OH)2D3 glycoside; and 100% = feed with 0,750 µg of 1,25(OH)2D3 glycoside. The levels of calcium (Ca) and phosphorus (P) in feed, feces and urine, total consumption of Ca and P, excretion of Ca and P, and digestibility coefficients of dry matter, crude protein, organic matter, Ca and P were analised. The zootechnical performance experiment used 128 hybrid piglets, whole males, with approximately 21 days of age and an initial average body weight of 6,82 ± 0,38 kg, distributed in a block design, with eight replicates and four animals per EU. The treatments were: 100/0 = 100% of vitamin D supplemented by cholecalciferol (2707 IU in the pre-initial I, 2405 IU in the pre-initial II and 1969 IU in the initial phase); 50/50 = 50% of the addition supplemented by cholecalciferol according to each phase + 0,25 µg of 1,25(OH)2D3 glycoside; 25/75 = 25% of cholecalciferol for each phase + 0,375 µg of 1,25(OH)2D3glycoside and 0/100 = 0,50 µg of1,25(OH)2D3 glycoside. Determination of initial body weight (IBW, kg), final body weight (FBW, kg), average daily consumption (ADC, kg day-1), average daily weight gain (ADWG, kg day-1) and the feed conversion rate (FC, kg kg-1). Were analyzed as calcium (Ca), phosphorus (P), alkaline phosphatase (AF) and 25(OH)D3 in the blood. At the end of the experimental period, 24 animals were slaughtered. How the carcasses were eviscerated and collected and weighed was mesured from the heart, liver, kidneys, intestines and spleen for the relative weight of the organs and pH of the gastrointestinal organs. The bones were collected for bone morphometric analysis. Comparisons between treatment media were performed using Tukey's test at the level of 5% or 10% probability. The β error of the parameters was used to help explain the values of 5 to 10% probability. The apparent digestibility of nutrients was not influenced (P> 0,05) by the controls, as well as the excretion of Ca2+ and P. The zootechnical performance of the

piglets shows differences between the tests for ADWGvariables (P=0,031) and for ADC (P=0,060) in the pre-initial phase I, FBW (P=0,095) and ADC (P=0,032) in the pre- initial phase I + II, ADC in the initial phase, ADC and feed convertion rate (FC) in the total period of the experiment. For plasma samples, or calcium in the pre-initial phase II (P=0,058), the highest concentration was in the 50/50 treatment. Alkaline phosphatase has a difference between treatments in the initial phase (P<0,001), with treatment 25/75 promoting the lowest plasma value (48163 U/L). A combination of the two forms of vitamin D resulted in a significant 9% increase in plasma calcium concentration in the pre-initial II. Effects were found for the relative weight of the spleen (P=0,032) with weight reduction in treatment 0/100 and effect (P=0,048) for the concentration of phosphorus in the organ. The heart showed an effect for dry matter (P=0,061), with greater concentration in the treatment 100/0. The pH demonstrated an effect (P=0,076), with a reduction in pH in the 50/50 treatment, in comparison with the higher pH values in jejunum (P=0,000) and ileum (P=0,002). The bone morphometry of the metatarsals presents differences in the epiphysis width (P=0,013), diaphysis height (P=0,068), diaphysis width (P=0,049) and size of the growth plate (P=0,002). There was an improvement in bone development with an increase of 0,7 mm in the growth plate and 6,6 mm in the width of the diaphysis of the bones of animals fed with an active form of vitamin D. Reduction of the relative weight of the spleen by 25,4% in the treatment with 1,25(OH)2D3 compared to treatment with cholecalciferol. Treatment 50/50 has the highest intestinal pH values. Follow treatment 0/100 which shows a 4,7% reduction in the pH of the jejunum and 7% in the ileum. In this context, the use of 1,25(OH)2D3 in supplementing analysis for readings is efficient in maintaining stomach and intestinal pH, as well as in bone development of animals. Furthermore, in view of the results found, it is suggested that there is an increase in piglet innate immunity due to the reduction in the size of the spleen, with little importance for this organ.