Mohsen Zaker_Jafari; Mehrdad Mohammadi; Maziar Mohiti-Asli
Volume 24, Issue 4 , December 2022, , Pages 477-488
Abstract
The effect of chick initial body weight and dietary nutrients density on growth performance and immune response were investigated using 360 Ross 308 one-day-old straight run chicks (mixed sex) in a completely randomized design with 2×3 factorial arrangement of treatments, four replicates and 15 ...
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The effect of chick initial body weight and dietary nutrients density on growth performance and immune response were investigated using 360 Ross 308 one-day-old straight run chicks (mixed sex) in a completely randomized design with 2×3 factorial arrangement of treatments, four replicates and 15 birds per replicate. The initial body weight of chicks was grouped as 42±1 g (standard weight); 38±1 g (light weight; 10% under standard weight); 46±1 g (heavy weight; 10% over standard weight) while the nutrients density of the diet was either 5% lower than the nutritional recommendation of Ross 308 (typical commercial diet in Iran), or as recommended by Ross 308 manual (high-density diet). Chickens fed the high-density diet had higher daily weight gain and lower conversion ratio than chickens fed the typical diets (P<0.05). The effect of dietary density and initial body weight of chicks on carcass components and weight of internal organs were not significant except for heart. Broilers fed the high-density diet and heavy weight had higher antibody titers to sheep red blood cell (P<0.05). Light chicks fed the high-density diets had greater total anti sheep red blood cell and immunoglobulin G titers than light chicks fed the typical diets (P<0.05). Results indicate that feeding light chicks with high-density diets increases their growth rate compared to the chicks with standard or heavy weights. Moreover, feeding diets with a high density of nutrients to light chicks can improve immune responses.
Ali Nazari; Hamed Ahmadi; Farid Shariatmadari
Volume 24, Issue 1 , April 2022, , Pages 59-65
Abstract
This study was performed to investigate the relationship between apparent digestibility of magnesium (Mg) with body weight, feed intake and phytase enzyme with 120 individual B-line Arian male broilers. Birds were assigned two standard diets and a diet supplemented with one gram of phytase (FTU / 500 ...
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This study was performed to investigate the relationship between apparent digestibility of magnesium (Mg) with body weight, feed intake and phytase enzyme with 120 individual B-line Arian male broilers. Birds were assigned two standard diets and a diet supplemented with one gram of phytase (FTU / 500 kg). Daily feed intake, weekly weight gain, feed conversion ratio during rearing and Mg digestibility were measured at 28 to 30 days. Using Gompertz model, growth rate (c), initial weight (b) and maximum growth potential (m) were analyzed. Growth rate and maximum growth potential were higher in the group consuming phytase enzyme (P <0.05). Weight gain and feed conversion ratio improved under the effect of phytase supplemented diets (P <0.05). Magnesium digestibility was higher in phytase enzyme diets than standard basal diets (P <0.05). The results showed that the modeled growth rate affected the Mg digestibility so that birds with higher growth rate (faster growth potential) had more potential for Mg digestion (P <0.05). The relationship between Mg digestibility and body weight gain was positive and the higher the Mg digestibility, the greater the weight gain (P <0.05). Birds with higher growth potential have the ability to digest more of the mineral Mg, and this digestibility is increased by the use of the phytase enzyme. Therefore, in the breeding programs of Arian chickens, more attention can be paid to the relationship between the use of magnesium and the growth rate parameter.
ali nazari; hamed ahmadi; farid shariatmadari
Volume 24, Issue 1 , April 2022, , Pages 59-65
Abstract
This study was performed to investigate the relationship between apparent digestibility of magnesium (Mg) with body weight, feed intake and phytase enzyme with 120 individual B-line Arian male broilers. Birds were assigned two standard diets and a diet supplemented with one gram of phytase (FTU / 500 ...
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This study was performed to investigate the relationship between apparent digestibility of magnesium (Mg) with body weight, feed intake and phytase enzyme with 120 individual B-line Arian male broilers. Birds were assigned two standard diets and a diet supplemented with one gram of phytase (FTU / 500 kg). Daily feed intake, weekly weight gain, feed conversion ratio during rearing and Mg digestibility were measured at 28 to 30 days. Using Gompertz model, growth rate (c), initial weight (b) and maximum growth potential (m) were analyzed. Growth rate and maximum growth potential were higher in the group fed phytase enzyme (P <0.05). Weight gain and feed conversion ratio improved under the effect of phytase supplemented diets (P <0.05). Magnesium digestibility was higher in phytase enzyme diets than standard basal diets (P <0.05). The results showed that the modeled growth rate affected the Mg digestibility, so that birds with higher growth rate (faster growth potential) had more potential for Mg digestion (P<0.05). The relationship between Mg digestibility and body weight gain was positive and with increasing Mg digestion, weight gain improved (P<0.05). Birds with higher growth potential have the ability to digest more Mg, and this digestibility is increased by the use of the phytase enzyme. Therefore, in the breeding programs of Arian chickens, more attention can be paid to the relationship between the use of Mg and the growth rate parameter.
Mohammad Panah; manocher souri; Samira Varahzardi
Volume 14, Issue 1 , September 2012, , Pages 33-40
Abstract
20 one-month-old Sanjabi suckling lambs (ten males and ten females with initial liveweight of 13.4 ± 1.3 and 11.6 ± 0.9, respectively) were used to assess the effect of ad libitum creep mixture on dry mater intake, live weight gain and carcass characteristics. The lambs were blocked within ...
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20 one-month-old Sanjabi suckling lambs (ten males and ten females with initial liveweight of 13.4 ± 1.3 and 11.6 ± 0.9, respectively) were used to assess the effect of ad libitum creep mixture on dry mater intake, live weight gain and carcass characteristics. The lambs were blocked within sex according to their live weight and randomly allocated to one of two treatments, control (free suckling and free choice of alfalfa) or supplementary (ad libitum creep mixtures with free suckling and free choice of alfalfa) in a 2 × 2 factorial arrangement. The study was continued for 100 days and at the end of the experimental period, all lambs were slaughtered to assess carcass characteristics. Average daily milk intake of males was higher than females (P< 0.01). Daily live weight gain (g/d) was significantly (P< 0.01) higher in males than females (240 vs. 163 g/d) and in the supplementary group than the control (259 vs. 145 g/d). Fat tissue in both male and female lambs in supplementary group was significantly (P< 0.01) more than that in the control. It could be concluded that the creep mixture diet improved growth rate and carcass characteristics and the fat content of the lambs.