Investigating dietary and metabolic factors related to ascites syndrome in broilers

Abstract:

In order to investigate dietary and metabolic factors related to ascites syndrome in broiler chickens, a research study was designed with 4 experiments.

The first experiment: 216 broiler chickens after 21 days of age were used in this experiment. After 21 days of age, 45 ppm of atenolol and lutyroxine in the diet and a control in two sexes were implemented in a completely randomized design, in a 3x2 factorial. During the experimental period, losses due to ascites were recorded, and blood was collected from the wing veins of the birds on the 42nd and 48th days. Also, at 48 days old, all birds were killed and the prevalence of ascites was calculated based on the weight ratio of the right ventricle to the total ventricles. The results showed that adding 45 ppm of lutyroxine to the diet caused a significant increase (P<0.05) in alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase in the blood compared to adding atenolol in the diet. The concentration of triiodothyronine hormone, hematocrit percentage, heterophil to lymphocyte ratio and weight ratio of right ventricle to total ventricles increased significantly (P<0.05) due to addition of lutyroxine and atenolol ratio. Addition of atenolol in the diet caused a significant decrease in the partial pressure of carbon dioxide in the blood and a significant increase in the partial pressure of oxygen in 48 days (P<0.05). Alkaline phosphatase enzyme activity and hematocrit percentage were significantly increased in roosters compared to chickens (P<0.05). Losses caused by ascites due to the use of lutyroxine increased significantly compared to the control. In this way, the use of atenolol caused a significant decrease in the amount of deaths due to ascites compared to the control (P<0.05). In the pre-test, levels of 0, 10, 20, 30, 40 and 50 mg/ml of arginine solution were injected into the yolk sac on the fifth embryonic day, and a treatment without injection was considered. On the 20th embryonic day, the pulmonary artery was sampled and the concentration of nitric oxide and endothelin 1 was measured and it was determined that the injection level of 20 mg/ml of arginine produced the highest concentration of nitric oxide and the lowest concentration of endothelin 1 in the pulmonary artery. In the main experiment, 20 mg/ml of arginine was injected into the yolk sac of 150 fertile eggs on embryonic day 5, and another 150 eggs were considered as controls. After hatching, the sex of the chicks was determined, and the experiment was carried out in the form of a completely randomized 2x2 factorial design (including injection and no injection × rooster and hen) in 4 replications and the number of 16 chicks in each replication. Before preparing the rations, the amount of amino acids of the feeds was measured and the rations were balanced based on arginine, methionine and lysine. After 21 days, in order to induce ascites, the temperature of the breeding hall was reduced to 15 ± 1 degrees. On the 21st and 48th days, blood was collected from 2 birds in each repetition, and on the 42nd and 48th days, the carcasses were dissected in order to sample the heart, lungs, and pulmonary artery. The results showed that before 21 days of age, only blood and serum viscosity decreased due to arginine injection, but after inducing ascites, the heterophil-lymphocyte ratio, hematocrit percentage, blood and serum viscosity, and thyroid hormone concentration decreased significantly due to arginine injection (P<0.05). The concentration of nitric oxide in serum increased only in 21 days due to arginine injection (P<0.05). However, the amount of arginine injection caused a significant increase in the concentration of nitric oxide and a significant decrease in the concentration of endothelin 1 in the pulmonary artery (P<0.05). The effects of gender on the concentration of nitric oxide and endothelin 1 in serum and pulmonary artery were not significant. The highest and lowest losses due to ascites were observed in treatments 1 and 4 (without arginine-rooster injection and arginine-chicken injection) respectively (48.8% and 17.6%, respectively).

Third experiment: This experiment was designed to compare arginine injection with the use of arginine dietary supplement on the resistance caused by ascites. 336 broilers were used in 5 treatments and 4 replications. The treatments included dietary arginine levels equal to the 1994 NRC and levels 5, 10 and 15% higher than the 1994 NRC recommendation, treatments 1 to 4, and injection of 0.The treatments included dietary arginine levels equal to NRC in 1994 and levels 5, 10, and 15% higher than the NRC recommendation in 1994, treatments 1 to 4, and injection of 0.50 cc of a 20 mg/ml arginine solution on the fifth embryonic day and rearing the resulting chicks with a diet containing amino acid arginine at the NRC level in 1994 (treatment 1) was considered as treatment 5. From 21 days onwards, in order to induce ascites, the temperature of the rearing room was reduced to 15±1°C. The results obtained from blood sampling on days 21 and 48 and carcass analysis on days 35 and 48 showed that the highest concentration of nitric oxide in the pulmonary artery was observed in treatment 3 (10% arginine higher than the NRC of 1994) (P<0.05) and no significant difference was observed between the concentration of nitric oxide in serum and pulmonary artery in treatments 3 and 5 (P>0.05). Similarly, the lowest concentration of endothelin 1 was observed in treatment 3, and no significant difference was observed between treatments 3 and 5. Before inducing ascites, the effects of the treatments on the ratio of heterophil to lymphocyte, hematocrit percentage, blood and serum viscosity, and thyroid hormone concentration were not significant (P>0.05). But after inducing ascites in the treatment of 3 and 5% hematocrit, the viscosity of blood and serum decreased significantly (P<0.05). The lowest concentration of triiodothyronine was observed in treatment 3 and the lowest concentration of thyroxine was observed in treatment 5. The amount of losses due to ascites showed a direct relationship with the weight ratio of the right ventricle to the total ventricles; So that the low weight ratio of the right ventricle to the total ventricles in treatments 3 and 5 was related to the reduction of losses due to ascites in these two treatments.

Fourth experiment: In this experiment, in order to investigate the effects of fatty acids with high omega-3 on resistance to ascites, 204 one-day-old male chicks were used in 3 treatments and 4 repetitions, and the number of 17 chicks was used in each repetition. became. Poultry fat was used in the diet at the level of 5.5% (with the ratio of omega-3 to omega-6 fatty acids of 0.201). Experimental treatments include 1- diet with 5.5% of waste oil. 2- Control diet + antioxidant and 3- Control diet + antioxidant + 10% arginine higher than the amount recommended by the NRC in 1994. The antioxidants used included vitamin E at the level of 150 international units of DL-alpha tocopherol, vitamin C at the level of 300 mg/kg, and organic selenium (Cellplex) at the level of 0.15 mg/kg, which was in the form of a plan It was used completely randomly in 4 repetitions. From 21 days onwards, in order to induce ascites, the temperature of the rearing room was reduced to 15±1°C. The use of arginine in treatment 3 increased the concentration of nitric oxide in the 48-day serum (P<0.05). Treatment 3 caused a significant increase in the heterophil to lymphocyte ratio, hematocrit percentage, blood and serum viscosity, and thyroid hormone concentration after ascites induction. Investigating the oxidative stress indices in blood and liver tissue showed that the addition of antioxidants in the diet in the 2nd and 3rd treatments reduced the antioxidant stress indices. Also, the conversion factor, the concentration of thyroid hormones and the activity of glutamate dehydrogenase enzyme in treatment 3 were higher than other treatments, which indicates the higher rate of metabolism in treatment 3. Examining losses due to ascites also showed that the highest rate of losses was observed in treatment 3. Although the addition of arginine in treatment 3 increased the concentration of nitric oxide, but the increase in metabolic rate caused by this treatment could not reduce the losses caused by ascites. Fetal feeding of arginine causes resistance to ascites more efficiently than arginine removal in the diet.

Key words: ascites, atenolol, luteyroxine, arginine, injection, nitric oxide, endothelin 1, pulmonary artery, omega 3, broiler.

Introduction:

One ??of the unique features of meat poultry that distinguishes it from other creatures is its high growth rate. In recent years, in order to increase the growth rate in meat poultry, advances have been made in the practical methods of genetics and disease control, so that today, in 45 days, a chicken with an average weight of 38 grams turns into a bird with an average weight of 2700 grams, that is, during this period, the initial weight becomes 71 times. High growth rate in broiler chickens is dependent on increased metabolic rate. The increase in metabolic rate is directly related to the amount of oxygen needed in this bird.