نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Introduction:Food restriction programs at the beginning of broiler breeding are one of the methods that can cause fat storage by reducing growth rate at the beginning of the growth period. For this reason, much research has been conducted to investigate different methods and programs of food restriction and understand how it affects various traits of broilers and quails. One of the common methods of applying food restriction is food restriction at the beginning of the period, which relies on the phenomenon of compensatory growth, and the results of studies show that early period restriction improves poultry performance. Numerous experiments have shown that after a period of restriction early in growth, chicks attempt to increase feed intake and use it more efficiently, thus improving feed efficiency and allowing for compensatory growth. Also, with improved feed efficiency, feed costs are reduced and there is a possibility of reduced abdominal fat due to reduced fat cell proliferation. Several factors affect the usable energy of fats, including the degree of saturation of fatty acids, the ratio of free fatty acids, the length of the fatty acid chain, the location of the fatty acid on the glycerol, the level of fat in the diet, moisture and impurities, oxidation, soap formation, and even the composition of the diet, such as the amount of non-starch polysaccharides. An experiment was designed to investigate the effects of oil on performance parameters and intestinal morphology of Japanese quail during compensatory growth period. Material and Methods: In this experiment, from 144 quail chicks were used and as a factorial test in a completely randomized design with 6 treatments and 4 replication were assigned to each treatment; Three levels of feed restriction (0, 15, 30%) from the age of 16 to 26 days were performed. Then each of these levels were divided into 2 group(Fat-free diet 1% ,Same energy in fat 4%). The starter diet was used to feed the chicks until the age of 49 days. These diets had 2900 kcal/kg of metabolic energy and 24% crude protein, respectively (the diet formulation in this experiment is based on the recommendation of)NRC, 1994). The metabolic energy of canola oil is 8800 kcal/kg and the metabolic energy of soybean oil is 8650 kcal/kg. The UFFDA computer software was used to adjust the diets based on NRC and formulate them. In this diet formulation program, it was tried to use similar foods as much as possible to avoid interactions between other nutrients that may affect the results of the experiment.Result and Discution:Dietary restriction imposed by decreased body weight in the treatment groups compared to the control group . feed consumption between the treatments (restriction 0%, fat diet 1%) during compensatory growth and adding oil (4%) had significant increase. The average feed intake of treatments) without fat)was 564.34 grams per bird, while the average feed intake of fat treatments was 152.611 grams per bird, and these differences were statistically significant (p<0.05). body weight mean and weight gain between the control (restriction 0%) and restricted treatments were not significant at the age 49 days, but there was an increasing trend with the intensity of feed restriction in treatments at compensatory growth. Regarding the adding oil, the body weight and weight gain improvement were observed. The highest body weight at 48 days of age was associated with the FR30 treatment (11/256) and the lowest weight was associated with the CR0 treatment (68/231). The interaction effects were not significant in any of the above conditions. Growth rate was significantly improved in feed-restricted chicks (1.5 vs. 0.94 as a percentage of initial weight). An improvement in growth rate was observed with the addition of fat to the diet.The significant improvement of feed conversion ratio was observed both in the case of feed restriction and in the case of oil usage. The differences became statistically significant with the addition of fat (p<0.05).analysis of the carcass the end of experiment revealed that, feed restriction had not significant effect on weight organs but with the intensity of feed restriction, reduce the abdominal fat pad. In examining the small intestine in two group in terms of villus height showed significant effect and with the addition of fat also increased villus height and thus absorption of nutrients. Also, with increasing severity of the restriction, the height, thickness, and depth of the crypt decreased.In generally ,the results of the study in whole period showed the use of restriction and also add fat had a positive impact on performance and carcass characteristics.
کلیدواژهها English
