نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشکده علوم دامی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان
2 دانشگاه علوم کشاورزی و منابع طبیعی گرگان
3 گروه تغذیه دام و طیور، دانشکده علوم دامی، دانشگاه گرگان
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Abstract
Introduction: Soybean meal has long been used as the most appropriate vegetable supplement to provide protein needs in animal rations. But due to the existence of problems such as product price fluctuations, foreign exchange leaving the country and the increase in the cost of ration, its use has faced limitations. Therefore, it is necessary to search for alternative items among the available domestic products. A high percentage of soybean meal, which has about 40% protein, is broken down in the rumen and its protein is broken down in favor of making microbial protein, which is undesirable. Agricultural by-products obtained from the extraction of vegetable oils, such as cottonseed meal, can be alternative options as a protein source for soybean meal. Cottonseed meal has lower levels of energy and protein than soybean meal, but it has more non-degradable protein in the rumen, and the use of passable protein in the diet improves access to the protein needed by the animal. Mixed meal is the name of a mixture that contains amounts of bloodless meat powder, cotton waste, rice bran, wheat bran, corn meal, pistachio powder and liquid gluten, and it can be used as a protein source in animal feed. The important advantage of this flour is to provide vegetable and animal proteins at the same time, and it seems that it can be one of the substitutes for vegetarian meals. Due to the high price and health issues, supplements of animal origin are used in small amounts in ruminant diets. So, making a combination containing both types of protein sources, in addition to reducing the price, will balance the proteins.
Materials and Methods: This study was conducted in order to investigate the effect of replacing soybean meal and cottonseed meal with mixed meal on feed intake, activity of hydrolytic enzymes, rumen parameters and liver enzymes of Dalagh ewes. Twenty one lactating Dalagh ewes in week 6 of lactation (average body weight ± standard deviation = 38±2.6 kg) were randomly divided into 3 groups with 7 repetitions. The treatments were included: 1) basic diet with soybean meal, 2) basic diet with cottonseed meal and 3) basic diet with mixed meal. The length of the test period was 42 days. Weighing of ewes was done at the beginning and at the end of the period. The rest of the feed is weighed every day and the daily feed consumption was calculated by deducting from the provided feed. Sampling of the rumen fluid was done on the 42th day. The rumen fluid was taken at three hours after feeding by esophageal tube, then the amount pH of rumen contents was measured and recorded immediately after extraction by a mobile digital pH meter (Metrohm laboratory pH meter-691) which was calibrated at the same place. In order to measure rumen liquid ammonia nitrogen, samples 3 hours after morning feeding were used. Dehority and Males method was used to count protozoa. The rumen fluid was filtered with a cloth in a test tube wrapped in foil, then 4 ml of rumen fluid was poured, then 1 ml of 18.5% formalin, 5 drops of methylene blue dye and 3 ml of glycerol were added. Counting of protozoa was done by a microscope and a lens with 40X magnification by a neobar slide. To measure the concentration of volatile fatty acids, 5 ml samples of rumen fluid were prepared and 1 ml of 25% metaphosphoric acid was added to them and kept at -20 degrees Celsius until the experiment. Rumin hydrolytic enzymes, including carboxymethyl-cellulase and microcrystalline-cellulase, were extracted according to the method of Hristov.
Results and Discussion: The results showed that the dry matter intake in the treatment receiving mixed meal increased compared to other treatments (P<0.05). Addition of mixed meal to the diet of ewes caused a significant decrease in rumen pH and a significant increase in ammonia nitrogen and rumen protozoa population compared to other treatments (P<0.05). Also, rumen acetate concentration decreased under the influence of mixed meal consumption, while rumen propionate concentration increased in the rumen of ewes receiving mixed meal (P<0.05). But the concentration of butyrate, isobutyrate, valerate, isovalerate and total rumen volatile fatty acids were not affected by the experimental treatments. The activity of carboxymethyl cellulose and microcrystalline cellulose enzymes in the cell section, extracellular section, solid part and total rumen parts in the treatments receiving soybean meal and cottonseed meal was higher than the treatment receiving mixed meal (P<0.05). No significant difference was observed between different experimental treatments in terms of aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase concentrations.
Conclusion: According to the present results, mixed meal can be completely replaced with soybean meal and cottonseed meal in the diet of Dalagh ewes without disturbing the feed intake and rumen health.
کلیدواژه‌ها [English]
)