Nutritional and Physical Improvements of Heat-Processed Pig Feeds and Feed Ingredients

Maxwell Stevenson (2012). Nutritional and Physical Improvements of Heat-Processed Pig Feeds and Feed Ingredients MPhil Thesis, School of Agriculture and Food Sciences, The University of Queensland.

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Author Maxwell Stevenson
Thesis Title Nutritional and Physical Improvements of Heat-Processed Pig Feeds and Feed Ingredients
School, Centre or Institute School of Agriculture and Food Sciences
Institution The University of Queensland
Publication date 2012-01
Thesis type MPhil Thesis
Supervisor Dr John Gaughan
Total pages 94
Total colour pages 16
Total black and white pages 78
Language eng
Subjects 070204 Animal Nutrition
Abstract/Summary The application of heat in processing pig feeds is a useful and necessary part of current milling methods and standards. With highly dynamic feed types and ingredients, correct application of heat is essential to ensure a uniform and accurately formulated diet. Rapid assessment of ingredients and understanding of interactions between ingredients is necessary in a production environment to ensure timely and efficient production. By using the Rapid Visco Analyser (RVA) to assess grain types and finished feeds it is possible to identify differences in pasting properties of individual grains. A total of six grain types including wheat, sorghum and barley varieties were tested using the same extended pasting profile. Finished feeds comprising diets of similar formulation containing either wheat or sorghum as an experimental component of the diet were heat treated to one of 4 levels including no heat treatment, low heat treatment (T65), medium heat treatment (T75) and high heat treatment (T85). Output results from the RVA show that there were recognisable differences that can be seen using the RVA for grain assessment as well as with finished feeds, although their relationship to grain chemistry and animal performance remains unclear. Finished feeds were either mixed and heat treated as a whole diet in a commercial mill or the grain component only treated in a commercial mill and mixed by hand. These diets were then assessed in three feeding studies using a total of 88 Large White × Landrace male pigs of approximately 4.5 weeks of age housed individually and fed ad libitum. Pig weights were recorded weekly over a 3 week period with residual feeds collected and weighed daily. Feeds were assessed for total starch, damaged starch and nitrogen content. Production responses varied between experiments. Rate of Gain (ROG) and feed:gain ratio (FCR) improved (P<0.05) when sorghum, treated at 75°C, was fed in mash form (Experiment 1) compared to no heat treatment. In contrast, mash and pelleted sorghum mixtures treated at the same temperatures (Experiment 2) showed numerical differences compared to wheat-based mixtures. Increasing the treatment temperatures from 65°C to 85°C and including these in mash diets had no significant effect on ROG but adversely affected FCR (P<0.05) and significantly reduced apparent DM digestibility (Experiment 3). In this study there was also a small difference (2.18%) in FCR in favour of wheat. As this was a small scale investigation conducted over multiple time periods care should be taken when interpreting results. A comparison of non-heat treated sorghum and wheat based diets fed as mash with the same diets treated at 75°C and fed as pellets showed that there were numerical but not statistical differences in animal performance between the grains and the effects of heat treatment. The results suggest that pelleting sorghum improved feed efficiency but that the opposite effect occurred for wheat. This difference in response should be considered in future descriptions of the feeding value of heat treated pig feeds, however more work will be required to validate the results.
Keyword Pig-feed
feed conversion efficiency
Additional Notes Colour Pages: 17, 21, 28, 31, 42, 44, 45, 46, 47, 48, 49, 51, 52, 66, 67, 68 Landscape Pages: 42, 43, 51, 52, 63, 65, 91

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Created: Fri, 20 Apr 2012, 12:59:06 EST by Mr Maxwell Stevenson on behalf of Library - Information Access Service