| dc.description.abstract | This thesis research was conducted to test the hypothesis that the survival and growth of both neonatal and postweaning piglets can be improved by nutritional modulations. Two experiments were carried out to 1) evaluate effects of birth weight on mortality, growth performance, and efficiency of sow-reared piglets; and 2) determine the effects of a phytochemical (Yucca schidigera) on growth performance of postweaning pigs. In the first experiment, piglets (n=160) from 18 multiparous sows (Landrace X Large White) were used. Body weight of all piglets were recorded immediately after birth, d 7, d 14, d 21 and d 35 of their age. Individual milk consumption of piglets was estimated using the weigh-suckle-weigh method. Average daily gain and mortality were recorded. To analyze the effects of birth weight on future BW and growth, piglets were classified based on their birth weight into four categories of A: 0.7-1.09 kg, B: 1.10-1.49 kg, C: 1.50-1.89 kg and D: >1.90. Data were statistically analyzed using one-way ANOVA. Results indicated that low birth weight of pigs not only increased (P < 0.05) their incidence of mortality but also negatively impacted (P < 0.05) their whole-body growth. Interestingly, surviving low-birth-weight piglets had a higher (P < 0.05) rate of efficiency to utilize milk nutrients for growth than larger littermates. In the second experiment, two 21-day trials using 21-d-old postweaning piglets (n=111) were performed (d 21 to 42 of age). In the first trial, pigs were assigned to one of the three groups fed diets supplemented with 0 (control), 120 ppm or 180 ppm of Yucca powder (BIOPOWDER). The second trial was conducted as the first trial except that the basal diet contained 0.2 percent L-citrulline (an effective precursor of arginine). Body weight, average daily gain and feed intake of all pigs were measured weekly in both trials. At the last day of experiment, 2 h after the last meal, jugular blood samples were taken from all pigs in both trials for amino acid analysis. One-way ANOVA was used to statistically analyze the data. When the basal diet did not contain citrulline, dietary supplementation with BIOPOWDER did not affect (P > 0.05) any of the measured variables related to growth performance. However, supplementing an appropriate dose of this yucca extract (120 ppm) to a citrulline-fortified diet increased growth performance and feed efficiency in these animals. Adequate availability of arginine is required for BIOPOWDER to exert its anabolic effect on piglet growth and its regulatory action on improving the efficiency of nutrient utilization in young pigs. These findings have important implications for nutritionally modulating the growth of neonatal pigs and, therefore, the swine industry worldwide. | en |
