نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم دامی، دانشکده علوم دامی و صنایع غذایی، دانشگاه علوم کشاورزی و منابع طبیعی خوزستان، ملاثانی، اهواز، ایران،
2 گروه علوم دامی، دانشکده علوم دامی و صنایع غذایی، دانشگاه علوم کشاورزی و منابع طبیعی خوزستان، ملاثانی، ایران.
3 گروه تحقیق و پژوهش در تغذیه حیوانات تک معده، آدیسئو، سینت فونس، فرانسه،
4 گروه علوم پایه دامپزشکی، دانشکده دامپزشکی، دانشگاه شهید چمران اهواز، اهواز، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction: The trend of incorporating cost-effective feed ingredients into poultry diets has led to the use of fibrous components. Dietary fiber significantly affects feed intake and nutrient digestibility in poultry, with the impact varying based on fiber type and inclusion level (Mateos et al., 2012). In broilers, a moderate inclusion of insoluble fiber aids in prolonging digesta retention time in the upper gastrointestinal tract, enhancing gizzard development and function, along with other digestive organs (González-Alvarado et al., 2008). Additionally, dietary fiber stimulates the production of hydrochloric acid and bile acids and improves amylase activity, leading to better nutrient utilization (Hetland et al., 2002). Insoluble fiber can form a spongy structure in the digesta, facilitating enzyme penetration (Sarikhan et al., 2010). This increases the surface area and accessibility of nutrients to enzyme activity, resulting in improved nutrient absorption, retention, and growth performance in birds. A well-developed gizzard also enhances reverse peristalsis, which churns food back up the digestive tract. This process is stimulated by the increased release of cholecystokinin, a hormone produced in the duodenum and pyloric area of the avian digestive system (Svihus et al., 2004). A reduced-crude protein (CP) diet for broiler chickens reared from 14 to 35 days post-hatch contains 2% to 3% less CP compared to conventional diets. These diets are typically formulated by decreasing soybean meal and increasing feed grains (such as maize or wheat), along with higher inclusions of non-bound (crystalline and synthetic) amino acids to meet nutritional requirements. Studies (Van Harn et al., 2017) have shown that CP reductions (20-30 g/kg) in Ross 308 broiler diets can be achieved without compromising live weight gain or feed intake. Notably, these diets even show a significant improvement in feed conversion ratio (FCR) with a 3.5% decrease. Modern broiler diets can achieve even greater CP reductions (around 30 g/kg) while maintaining performance, allowing for a substantial decrease in dietary soybean meal inclusion (over 30%) (Chrystal et al., 2020). Dietary fiber with increased particle size may enhance foregut development more effectively in poultry fed diets moderately low in crude protein. This study investigates the performance of broilers fed on low-density crude protein diets with increasing particle size of sunflower hulls.
Materials and Methods: This experiment aimed to examine the effect of sunflower hull particle size on the performance and physiological response of broiler chickens fed with different protein levels. A completely randomized design was used with a 3 × 2 factorial arrangement, comprising 6 treatments (6 replicates per treatment, 10 birds per replicate). The treatments included 3 types of dietary sunflower hull types (without hulls, 4% with 1 mm particle size, and 4% with 5 mm particle size) and 2 crude protein (CP) levels (normal and a 10% reduction). Feed intake (FI) and body weight gain (BWG) were recorded, and the feed conversion ratio (FCR) was calculated. To determine ileal nutrient digestibility, chickens were fed 3 g/kg of chromium oxide from days 21 to 25. On day 25, ileum contents from 2 birds per replicate were collected and stored at -20°C. The cecal microbial population was assessed at 42 days of age. Data were analyzed using SAS software and the GLM procedure. Duncan's multiple range test was used for mean comparison at a 5% significance level.
Results and Discussion: The results indicated that incorporating sunflower hulls (SFH) in the diet increased FI, except during the starter period, and improved FCR in both the starter and grower periods. Broilers fed coarse SFH showed increased relative weights of the carcass, gastrointestinal tract, gizzard. The apparent digestibility of crude protein improved by coarse SFH with low crude protein. Both fine and coarse SFH in the diet enhanced the Lactobacillus population.
Conclusion: Overall, the study results indicate that adding coarse sunflower hulls to the diet can enhance broiler growth performance. This improvement is achieved by increasing the digestibility of crude protein, as well as boosting the Lactobacillus population. Additionally, using coarse sunflower hulls led to an increase in the relative weight of the carcass and thighs.
Materials and Methods: In this experiment, in order to examine the effect of sunflower hulls particle size on performance parameters and physiological response of broiler chickens fed with different levels of protein, in a completely randomised design was used, with a 3 × 2 factorial arrangement of 6 treatments (6 replicates per treatment, 10 birds per replicate) involving 3 dietary sunflower hulls (without hulls, 4% with 1 mm particle size and 4% with 5 mm particle size) and 2 CP levels (normal and low with 10%-units CP reduction). Feed intake (FI) and body weight gain (BWG) of birds were recorded and feed conversion ratio (FCR) was calculated. To determine the ileal digestibility of nutrients, 3 g/kg of chromium oxide was fed to chickens on days 21-25 of the rearing period. On the 25nd day of rearing, the ileum contents of 2 birds were collected and stored in a freezer at -20◦C. Cecal microbial population also determined at 42 days of age. The data obtained from the experiment were analyzed using SAS statistical software and GLM procedure. To compare means, Duncan's (1955) multi-range test was used at a significant level of 5%.
Results and Discussion: The results showed that, using of the coarse SFH in the diet of broiler chickens increased FI except the starter period and improved the FCR in the starter and grower period of experiment. Broilers fed the coarse SFH increased relative weight percentage of carcass, thighs, GIT, gizzard and abdominal fat. Apparent digestibility of dry matter, nitrogen and crude fat increased by using of coarse SFH in the diet. The use SFH (fine and coarse) in the diet increased the population of Lactobacillus.
Conclusion: In general, the results of the present study showed that the addition of coarse sunflower hulls to the diet could improve the growth performance of broilers by increasing the digestibility of nitrogen, crude fat, Lactobacillus population. The use of the coarse sunflower hulls increased the relative weight of the carcass and thighs.
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