| Corn distiller’s dried grains with solubles (corn DDGS) is a by-product of the dry-milling fuel ethanol plants. During the production of ethanol, starch is converted to alcohol and carbon dioxide, as a result, the concentration of remaining nutrients in corn DDGS increases by approximately threefold. Corn distillers dried grains with solubles is a valuable source of crude protein, fat and available phosphorus for livestock. Recently, with the development of processing technology, the quality of corn DDGS is improved and has increasingly been included in swine diets. However, the corn DDGS inclusion in growing-finishing diets may reduce growth performance because of the poor amino acids profile, high crude fiber content and nutrients variability in corn DDGS. Also, the high unsaturated fatty acids content, especially linoleic acid (18:2), may have a negative effect on pork quality. The trial was conducted to investigate the effects of corn DDGS and allzyme SSF supplementation on growth performance, fat quality and fatty acid composition in growing-finishing pigs. This thesis was described in the following three sections.In the first section, the feeding trial was conducted to investigate the effects of corn DDGS and allzyme SSF supplementation on growth performance, nitrogen and phosphorus digestibility and feed cost in growing-finishing pigs.200pigs (Duroc×Landrace×Yorkshire) at the age of70days, with an average initial body weight of28.75±3.11kg, were randomly allotted to one of four dietary treatments on the basis of BW and gender. The control dietary was a basal corn-soybean meal diet. Treatment1,2and3were corn-soybean meal-DDGS diet, with10%corn DDGS in growing phase and15%in finishing phase, respectively.200g per ton of SSF was added to the diets of treatment2and3and the energy level of treatment3was reduced50kcal per ton. The results showed that all groups had comparable results (P>0.05)on ADG (682.15g,671.99g,709.28g,700.29g), ADFI (2.00kg,2.02kg,2.04kg,2.10kg) and F:G (2.94,3.01,2.88,3.00). The corn DDGS and SSF supplementation increased P digestibility (P<0.05), but tended to increase N excretion and reduce N digestibility (P<0.05). In conclusion, corn DDGS inclusion had no detrimental effect on growth performance in growing-finishing pigs, but reduced the feed cost. Also, feeding corn DDGS increased P digestibility and N excretion. The SSF supplementation could improve the availability of the corn DDGS, increase the ADG and reduce P excretion.In the second section, effects of corn DDGS and allzyme SSF supplementation on fat characteristics of carcass were investigated. The results showed that corn DDGS inclusion in growing-finishing pigs diet had no effect on backfat depth (P>0.05), but significantly increased iodine value and reduced fat melting point (P<0.05). Also, intramuscular fat in longissimus dorsi, psoas major, biceps femoris decreased significantly (P<0.05). The results showed that corn DDGS supplementation had negative effect on fat quality, but still produced an acceptable level. Allzyme SSF didn’t recover the effects induced by corn DDGS supplementation.In the third section, automatic biochemistry analyzer and gas chromatography were used to investigate the effects of corn DDGS and allzyme SSF supplementation on blood-fat level and fatty acid profile in growing-finishing pigs. The results showed that CH and LDL level increased in treatment3compared with other groups (P<0.05), TG and HDL level were not different for corn DDGS and allzyme SSF supplementation. Feeding DDGS and SSF increased unsaturated fatty acids (especially oleic acid and linoleic acid)(P<0.05) and decreased saturated fatty acids (especially palmitic acid and stearic acid)(P<0.05) in longissimus dorsi and backfat. Treatment3had the highest unsaturated fatty acids content compared with other three groups. In conclusion, feeding corn DDGS increased unsaturated fatty acids content in tissues, especially treatment3. |
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