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Thursday, October 21, 1999
FULL TEXT PAPER
Swine Nutrition Research Studies
by Various Researchers
- Reduced Protein Diets for Nursery Pigs (D. H. Baker and Ioannis Mavromichalis) We managed to reduce for the first time the crude protein concentration of a typical corn-soybean meal-whey diet for 10 to 20 kg pigs by 6% using a crystalline amino acid mixture that contained valine among other amino acids (i.e., lysine, methionine, threonine, and tryptophan).
- Valine Requirements of Nursery Pigs (D. H. Baker and Ioannis Mavromichalis) We investigated the valine requirements of nursery pigs; based on the results of the first project the valine requirements proposed by NRC-1998 might be underestimated.
- Digestibility of Sow's Milk (D. H. Baker and Ioannis Mavromichalis) We will determine the digestibility of nutrients in sow's milk with young pigs (ca. 5 kg) as a first step in developing a new diet for early weaned pigs that will match better their nutrient requirements.
- Early Feed Intake (D. H. Baker and Ioannis Mavromichalis) We investigated several management procedures to increase early postweaning feed intake. Current results indicate that growth performance can be greatly enhanced if pigs are offered feed on a tray for the first few days postweaning.
- Zinc Oxide Sources (D. H. Baker and Ioannis Mavromichalis) We test two sources of zinc oxide that differ vastly in bioavailability (30 vs 90%) as growth promotants for early weaned pigs.
- Step-Phase Feeding Program (D. H. Baker and Ioannis Mavromichalis) We develop a new nursery feeding program that uses several combinations of only two diets (complex and simple) to more closely match the nutrient requirements and digestive capacity of nursery pigs.
- Feed Deterioration by Pelleting and Storage (D. H. Baker and Ioannis Mavromichalis) We determined that storing a complex nursery diet in the hot and humid environment of a typical nursery facility for one week deteriorates lysine bioavailability by 10%, whereas pelleting the same diet to a diameter of 5 mm did not affect lysine bioavailability.
- Pellet Sizes for Nursery Pigs (D. H. Baker and Ioannis Mavromichalis)We investigate the effects of different pellet sizes (from 2 to 6 mm) on nursery pig performance and on lysine bioavailability.
- Phytase and Trace Minerals (D. H. Baker and Ioannis Mavromichalis) We are testing the hypothesis that phytase might be able to release enough trace minerals (i.e., iron, copper, zinc, and manganese) from corn and soybean meal that supplementation of diets with trace mineral premixes might become obsolete, from weaning to market age.
- Side-Effects of Vaccinations...We determined that vaccinating pigs at weaning as opposed to one week before weaning does not reduce growth rates but causes a drop in feed intake three to four days postweaning.
- DEVELOPMENT of HOST-MICROBIOTA INTERACTIONS in the PIGLET INTESTINE Gaskins, H.R.; Mackie, R.I.; Gelberg, H.B. University of Illinois, Urbana-Champaign; Department of Animal Sciences; Urbana, IL 61801 The neonatal period presents a formidable challenge to the swine industry. Twelve to 30% of liveborn piglets do not reach weaning age and those that do rarely reach their growth potential resulting in substantial production losses. Although neonatal deaths and growth stasis reflect numerous interactions between the piglet and its new environment, delayed intestinal development resulting in enteric compromise is a major underlying cause. Our proposal focuses on the development of the two major tiers of intestinal defense-the normal gut microbiota and the mucosal immune system. Addressed is the working hypothesis that a parallel and interactive relationship exists between succession of the normal adherent microbiota and the development of epithelial cell immunocompetence in the piglet intestine. An interplay between the host and its resident microbiota likely involves a complex signaling program between the two partners. As yet, we do not understand mechanisms underlying this reciprocal signaling process. To address those questions, our proposal brings together multidisciplinary expertise that features accomplished backgrounds in immunology, gastrointestinal microbiology, and intestinal biology. Molecular probe technology that overcomes long-standing methodology limitations in gut microbial ecology will be used to investigate concurrently the spatial and temporal development of the resident gut microbiota and the molecular basis of host-microbe interactions at the epithelium. Our research will develop the theory and lay the groundwork for unique biotechnological strategies to regulate the development of mucosal defense in the intestine and thereby offer the swine industry novel means to stimulate pig growth from birth through the weaning transition.
- The efficacy of phytase supplementation to finishing swine diets in which sources of inorganic phosphorus have been removed and trace mineral supplementation has been reduced. (C.M. Peter and D.H. Baker) Experiments were conducted to determine the effects on growth performance, bone composition, and carcass characteristics in late finishing swine. A nutrient balance experiment was also performed to determine these effects on nitrogen, calcium, phosphorus, and trace mineral absorption and retention. Laboratory analyses are currently in progress.
- The efficacy of organic acid and phytase supplementation, alone or in combination, on phytate-phosphorus utilization in young chicks and pigs. (C.M. Peter and D.H. Baker) Experiments were conducted to evaluate the effects of phytase alone, citric acid alone, or the combination in liberating phytate-bound phosphorus (P) in nursery pigs (10-20 kg) fed P-deficient corn-soybean meal diets. The treatments consisted of three levels of phytase inclusion (0, 500, or 1000 U phytase/kg diet) fed in the presence or absence of 2 % citric acid. Weight gain, feed intake, gain:feed, bone ash (mg), and bone ash (%) were increased with the addition of phytase to the P-deficient basal diet. Additionally, weight gain, bone ash (mg) and bone ash (%) were higher for pigs fed 1000 vs. 500 U phytase/kg diet, although no effects were observed for feed intake and gain:feed. The addition of citric acid to the P-deficient basal diet resulted in increased weight gain and feed intake, and a trend towards increased gain:feed. Furthermore, supplementing 2 % citric acid and 500 U phytase/kg diet in combination resulted in similar weight gain, feed intake, and gain:feed responses as supplementing 1000 U phytase/kg diet alone. Similar assays involving formic acid supplementation are currently being undertaken.
- The effects of phytase and organic acid supplementation on crude protein-amino acid utilization in swine and poultry diets. (C.M. Peter and D.H. Baker) Several assays were conducted to evaluate the effects of microbial phytase on crude protein-amino acid utilization of soybean meal in chicks. The experiments were conducted using a 3 x 2 factorial arrangement of treatments, consisting of three levels of crude protein (5, 10, 15 % CP) supplied by soybean meal fed in the presence or absence of 1200 U phytase/kg diet. Weight gain, gain:feed, and whole-body protein accretion were regressed on crude protein intake, multiple linear regression analysis was performed, and slope-ratio methodology was applied for graded levels of crude protein fed in the presence or absence of 1200 U phytase/kg diet. Weight gain, feed intake, gain:feed, and crude protein accretion increased linearly as a function of crude protein intake, but phytase supplementation did not affect the slopes of the accretion curves. These data indicate that phytase supplementation did not increase the protein-amino acid utilization in soybean meal for young chicks. Similar assays are currently ongoing to evaluate the effects of organic acid supplementation in chicks and the addition of phytase in pigs on the crude protein-amino acid utilization of soybean meal.
- The effects of phytase on protein utilization in corn and corn co-products. (C.M. Peter and D.H. Baker) Several assays are being conducted to determine the effects of phytase on the protein quality of corn and corn gluten meal. Additionally, the limiting order of amino acids in corn gluten meal is being established.
- Nutritional evaluation of genetically enhanced corn hybrids and their potential impact in ruminant and nonruminant diets. (C.M. Peter and D.H. Baker) Chick and swine bioassays are being conducted to establish nutritional profiles of several new varieties of low-phytate, high-oil, and high-protein corn hybrids. Nutritional assessments will include the determinations of relative phosphorus bioavailability, protein quality, and metabolizable energy content. Furthermore, samples of corn gluten feed derived from genetically enhanced corn hybrids are also being evaluated for their potential impact in ruminant diets.
- Development of a quantitative assay for determination of inorganic phosphorus (Pi) and development of a two-step assay for determination of Pi, followed by total phosphorus (Pt) quantification. (C.M. Peter and D.H. Baker) Current analytical techniques only allow for the qualitative determination of Pi. Various methods are available for the assessment of Pt, however these techniques do not always yield similar values. Current research involves the development of a quantitative assay for Pi determination using standardization methods; the determination of the most precise, accurate, and reliable method of Pt assessment; and potential development of a two-step assay for Pi and Pt determination. Our goal is to develop a quick and easy method by which grain and soybean meal handlers (commodity companies, feed manufacturers, county and private elevators) can easily distinguish between phytate and non-phytate phosphorus.
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