The Effect Of The Dietary Energy And Protein Level On Nitrogen Deposition And Nitrogen Excretion Of Broilers At The High Environmental Temperature

The experiment were designed into three trials and investigate the effect of thedietary energy and protein levels on growth performance and carcass performance,nitrogen metabolism and ammonia generated of broilers at the high environmentaltemperature.In Exp.1, the effect of the dietary energy and protein levels on growth performanceand carcass performance of broilers at the high environmental temperature.360AAbroilers were selected and randomly allocated into nine treatment groups when theywere3weeks of age, each group included four replicates,and each replicates contained10chickens.Test includes two factors, dietary metabolizable energy (ME:3000,3200,3400kcal/kg) and crude protein level (CP:18%,20%and22%). the wholeexperiment started on29-day-old broiler and the end of the42-day-old, Broilers are keptin sheds where the Cyclic High Temperature is elevated in a day.Determined the growthperformance and the carcass performance of broilers in the first week and the secondweek.The results showed that：the dietary crude protein levels had no siginificantlyimpact on broiler average daily feed intake, average daily gain and feed to gain ratio（P>0.05）, but at the same crude protein level conditions, With increasing dietarymetabolizable energy level, broiler average daily feed intake was significantly higher(P<0.05), feed conversion ratio but reduced (P<0.01). Compared with low energy levels,high-energy diets significantly improved broiler abdominal fat percentage (P<0.01),Abdominal fat percentage dropped with the improvement of protein levels. Dietarymetabolizable energy and crude protein levels on growth performance and carcassperformance of broiler had no significant interactive effects. This indicates that the hightemperature environment, in the case of essential amino acids are to meet the needs ofthe animal, when dietary energy concentration or decrease200kcal/kg and crudeprotein level is raised or lowered by2percentage points, there is no significant impacton the growth of broiler, but feed intake and feed conversion ratio are significantdifferent.And when dietary crude protein level is raised or lowered by2percentagepoints,there is not significant impact on the broiler breast muscle and leg muscle rate,theconcentration of dietary energy and crude protein were significantly affect the rate ofabdominal fat.In Exp.2, the effect of the dietary energy and protein level on nitrogen metabolism of broilers at the high environmental temperature.The design of experiment was thesame as Exp.1. Determined the contents of total protein, uric acid, urea nitrogen,triglyceride and cholesterol in serum of broilers and the contents of uric acid and ureanitrogen in excreta and Intestine of broilers in the first week and the second week.Determined the broiler body protein deposition rate between the treatment groups.Theresults showed that: the dietary energy and protein levels had no siginificantly impacton the contents of uric acid and urea nitrogen in intestine and each indicator in serum（P>0.05）. Compared with the concentration of low-energy, the content of ureanitrogen in excreta was significantly higher in the first week (P<0.01), but it had lowerlevels on the content of uric acid in the second week. The total protein intake (P<0.05),and the discharge of total protein (P<0.01) were significantly lower in the high energygroup, body protein deposition rate was highest when the level of dietary energy is3200kcal/kg. Compared with low dietary protein level, high-protein group broiler totalprotein intake and discharge of total protein were significantly increased (P<0.01), butthe broiler body protein deposition rate and protein retention rate had decreasedsignificantly (P<0.05). Dietary metabolizable energy and crude protein levels on theindicators of broiler had no significant interactive effects. This indecates that at the hightemperature environment,in the case of essential amino acis to meet the animalsneed,when dietary crude protein levels reduce or when the energy levels increasenitrogen excretion can significantly reduce;also shows that at the high temperatureenvironment, in the case of essential amino acis to meet the animals need,with thedietary crude protein level reducing,the protein deposition rate and protein retention rateare higher. Dietary metabolizable energy and crude protein levels on the nitrogenmetabolism of broiler had no significant interactive effects.In Exp.3, the effect of the dietary energy and protein level on ammonia generatedin vivo and excretion of broilers at the high environmental temperature.The design ofexperiment was the same as Exp.1. Determined the content of ammonia nitrogen in theserum, in the Intestinea and in the excreta; determined the activity of urease and uricasein the Intestinea excreta. The results showed that: the content of ammonia nitrogen inthe serum, in the intestinea and in the excreta had no significant difference (P>0.05), butwith the dietary crude protein level increasing, the unit intake contents of ammonianitrogen in excreta of broiler chickens is higher.the urease activity of the diets highenergy group was lower, it did not reach a statistically significant level (P>0.05),compared with low dietary energy concentration, the excreta urease activity of thehigh-energy group broiler significantly increased (P<0.05), Dietary metabolizableenergy and crude protein levels on the ammonia generated in vivo and excretion ofbroilers had no significant interactive effects. This indecates that at the high temperatureenvironment,in the case of essential amino acis to meet the animals need, the content ofammonia nitrogen in the excreta can reduce to a certain extent when the dietary crudeprotein levels reduced. Dietary metabolizable energy and crude protein levels on theammonia generated in vivo and excretion of broilers had no significant interactiveeffects.