Document Type : Research Paper
Authors
1 Corresponding Author, Department of Animal and Poultry Nutrition, Faculty of Animal Science, Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran. E-mail: ma.shahi@gau.ac.ir
2 Department of Animal and Poultry Nutrition, Faculty of Animal Science, Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran. E-mail: ghoorchi@gau.ac.ir
3 Department of Animal and Poultry Nutrition, Faculty of Animal Science, Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran. E-mail: toghdory@gau.ac.ir
4 Department of Animal Science, Agriculture Faculty, Ferdowsi University of Mashhad, Mashhad, Iran. E-mail: shebrahimi@um.ac.ir
Abstract
Introduction: Cottonseed is a valuable feed ingredient due to its high fiber and energy content, which can enhance the energy and protein levels in animal diets. In the irradiation or micronization method, using infrared rays and without damaging the fat cells, while maintaining the profile of fatty acids, the seed is heated, and its anti-nutritional factors are destroyed. Sodium hydroxide treatment can affect ruminal degradability and nutrient digestibility, ultimately influencing performance. This study aimed to assess the impact of feeding processed cottonseed on the performance, blood parameters, nutrient digestibility, and feeding behavior of fattening male lambs.
Material and Methods: The study was conducted at the animal husbandry facility in Ghala Khan village, North Khorasan province. For this purpose, 40 Afshari male lambs (4-6 months old) with an average weight of 27.6±4 kg were randomly allocated to four treatments with ten replications for 84 days. The experimental treatments included: 1) diet containing whole cottonseed, 2) diet containing ground cottonseed, 3) diet containing micronized cottonseed, and 4) diet containing sodium hydroxide-treated cottonseed. For irradiation, 5% of drinking water was added to the cottonseed and it was rotated inside a cylinder for 10 minutes at a speed of 20 revolutions per minute until the water was completely absorbed by the seed. Then, the seeds were exposed to infrared radiation with an irradiation distance of 12 cm for 60 seconds in a gas flicker micronizer and immediately after leaving the micronizer, they were placed between two metal rollers. They were pressed and filled at a distance of 1 mm. The chemical processing of the foam samples was done in such a way that first a 4% solution of sodium hydroxide (40 grams of sodium hydroxide in 100 milliliters of distilled water) was prepared. This solution was mixed with cottonseed samples to obtain four grams of sodium hydroxide per 100 grams of dry matter of cotton seeds, and then it was kept and dried in open air for 48 hours. Lambs were kept in individual stalls during the experiment and had free access to water during the period. Fecal and feed samples were collected during the last week of the experimental period for determining digestibility. Insoluble fiber levels were determined using Van Soest's method, and nutrient digestibility was assessed using acid-insoluble ash as an internal marker. Blood samples were collected on the last day and before morning feeding. Feeding behavior (resting, rumination, chewing, eating) of the lambs was measured continuously for 24 hours on the last two days of experiment.
Results and Discussion: The micronized cottonseed increased final weight as well as dry matter digestibility (P<0.05), and improved feed conversion ratio. There was no significant difference in feeding behavior in lambs fed with different treatments of cottonseed. Blood cholesterol, triglyceride and urea levels were highest in lambs fed micronized cottonseed and lowest in those fed whole or ground cottonseed (P<0.05). Conclusions: Our findings indicated that micronized cottonseed and processing of cottonseed by sodium hydroxide could increase daily weight gain and improved the feed conversion ratio in fattening lambs, suggesting their potential inclusion in feedlot diets.
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