عنوان مقاله [English]
Introduction Flax products (seeds and meal) are one of the sources of energy and protein for ruminants. Although flaxseed is a very inexpensive and affordable source of omega-3s, more than 50 percent of its fatty acids are made from alpha-linolenic acid, but it cannot be used at high levels due to its anti-nutritional properties. Flaxseed processing improves nutrient consumption while reducing the negative effects of anti-nutritional substances such as lintine and makes food more palatable. Various methods are used to process and improve the flaxseed digestion process, such as micronization and extrusion. The extrusion process is in fact the process of processing high temperature materials in a short time and is done by a combination of moisture, heat, mechanical energy and pressure. Extrusion is also a technical function by which feed is processed, extruded and cooked under a constant increase in pressure and then expanded due to a sudden drop in pressure. Heat treatment applied during the extrusion process reduces the access of rumen bacteria to the fat in the diet by denaturing the protein matrix around fat droplets in oilseeds such as flaxseed, and thus can reduce fatty acids. Protect unsaturated with several double bonds from ruminal biohydrogenation. Microwave by microwave can be done after adding 25% moisture to the grains for 3 minutes in a device containing an infrared lamp. It was also found that micronization could be used to increase the degradable protein content of the rumen. This study was performed to evaluate different levels and methods of flaxseed processing in the diet on performance, nutrient digestibility, blood parameters and sheep ruminant behavior.
Materials and Methods 42 adult Moghani ewes with an average initial weight of 47 ± 2.8 kg were divided into seven treatments and six replications in a completely randomized design. Treatments include: Control treatment without flaxseed, 5% of raw flaxseed (not processed), 10% of raw flaxseed (not processed), 5% of processed flaxseed Micronized method, 10% of flaxseed processed by micronized method, 5% of flaxseed processed by extrusion method and 10% of flaxseed processed by extrusion method. The duration of the course was 60 days, of which 15 days were habituation and 45 days were experimental. Diets were adjusted based on NRC (44). All ewes were placed under the same management and feeding conditions. Diets were given to the ewes twice daily, at 8 am and 4 pm after weighing the ewes. Livestock was also held individually in livestock cages and had free access to water. Feed was given and the remaining feed was weighed and recorded for each animal each day. Daily feed intake was calculated from the average difference of feed given for each livestock and the rest of the manager the next day. The mean of each treatment was calculated from the average feed consumption of each animal during the period. Dietary digestibility was measured by the internal marker of acid-insoluble ash in the last 3 days of the experiment and blood and ruminal fluid samples were taken on the last day of the experiment. Dietary digestibility was measured by internal marker of acid-insoluble ash in the last 3 days of the experiment and blood samples were taken on the last day of the experiment. In the last two days of the experiment, rumination behavior was measured by recording activity for a period of 24 hours. Data were analyzed using SAS software version 9.9 (54) using GLM procedure.
Results and discussion Different levels and processing of flaxseed had no significant effect on weight, dry matter intake, daily weight gain and feed conversion ratio. The highest dry matter intake and daily weight gain were related to treatments containing 10% extruded flax and 10% micronized flax, which indicates that the processing resulted in better flaxseed palatability. The use of different levels and methods of flaxseed processing in the present study did not have a negative effect on feed intake, which probably the amount of fatty acids and flaxseed fatty acid pattern used in this short-term study had minimal effect on the feed intake mechanism. Glucose and urea nitrogen levels were affected by experimental treatments. The addition of flaxseed increased blood glucose levels. This increase is likely due to the production of more propionic acid than rumen acetate. Studies have shown that ruminal fatty acids are biohydrogenation and increase propionate relative to acetate by altering ruminal fermentation pattern. The main precursor for gluconeogenesis activity in the liver is propionate, which stimulates glucose production. Propionate is a volatile fatty acid produced in the rumen that is a major precursor of glucose in animals. Increasing unsaturated fatty acids due to flaxseed consumption improves the energy status of the animal and reduces the deamination of tissue amino acids for energy supply and ultimately reduces the nitrogen level of blood urea. Dry matter and crude fat digestibility were affected by experimental treatments. The oil in flaxseed is coated and will not interfere with ruminal function, so it is not expected to have a negative effect on nutrient digestibility and even improve it in some cases. With increasing the use of flaxseed, the digestibility of insoluble fibers in neutral detergent decreased, which higher levels of unsaturated fatty acids in flaxseed can be a good reason to reduce the digestibility of insoluble fibers in neutral detergent and can be inferred as follows. Due to the increase in unsaturated fatty acids, ruminal fibrolytic activity is affected and due to the addition of flaxseed, cell wall digestibility is reduced. Experimental treatments could not have a significant effect on the ruminant behavior of ewes.
Conclusion According to the results of this experiment, extruded and micronized flaxseed at the level of 10% can be used as a source of energy and protein in ewes' diets.