Effects Of Arginine Infusion In Duodenum On Nitrogen Balance And ¹³C-Phe Oxidation Rate In Fattening Lambs

The aim of this study was to use the method of duodenal infusion of amino acid to investigate the restriction of arginine on the nitrogen deposition of Kazakhstan under actual feeding conditions.Useing the indicator amino acid oxidation technology to discuss the Kazak sheep in the routine feeding conditions on Met and Lys requirements.The purpose of this study was to provide the basis for improving the utilization efficiency and production performance of growing lambs.Experiment 1:Five Kazakh male lambs?29.4 ± 1.76 kg of body weights and 4 months old?were fitted with duodenal cannulae and raised in metabolic cage individually.The experiment was conducted in a 5×5 Latin square design with five lambs,periods were 7d.Treatments were continuous duodenal infusions of a solution?500 mL/d?containing 1)no AA?CON?,2)a mixture of 8 essential AA?8EAA?,3)8EAA with Lys removed?-Lys?,4)8EAA with Arg removed?-Arg?,5)8EAA with Met removed?-Met?.We studied the effects of five kinds of different amino acids perfusion fluid from duodenal fistula on nitrogen deposition and plasma urea nitrogen?PUN?under the condition of actual feeding.In the experiment,Fecal N excretion was not different,and urinary N excretion,N retention?g/d,and% of total N intake?,PUN concentration,and apparent N digestibility was greater?P<0.05?for lambs receiving 8EAA vs.CON.Nitrogen retention?g/d?decreased?P<0.05?in response to the removal of Arg,Met and Lys,decreased by 30.6 %?11.56 %?12.98 %,respectively.Daily gain?g/d?decreased but not significant?P>0.05?in response to the removal of Arg,Met and Lys,decreased by 13.89%?7.78%?6.58%,respectively.PUN concentration was greater?P<0.05?for lambs receiving 8EAA vs.CON,PUN concentration increased but not significant?P>0.05?in response to the removal of Met,Arg and Lys.Comprehensive evaluation of actual fattening conditions Arg,Met and Lys has restricted effect to kazakh lamb fattening.Experiment 2:Arginine has been demonstrated being the limiting amino acid for growing sheep when microbial protein is the predominant source of absorbable AA,but its specific requirement has not been well quantified.The objective of this experiment was to estimate the growing sheep requirement of Arg using the IAAO method.Five Kazakh male lambs?35.4±1.5 kg of body weights?were fitted with duodenal cannulae and raised in metabolic cage individually.The experiment was conducted in a 5×5 Latin square design.Each period lasted 5 days.The indicator AA oxidation trials was conducted in which the lambs were duodenally infused graded amounts of Arg.After a 1-2 d adaptation period,the IAAO test was conducted on d 3.Each lamb received a priming dose of 0.67 mg/kg BW of ¹³C-Phe injected via the jugular vein,together with 0.18 mg/kg BW of 13C-NaHCO3 at time 0.And then perfused by a peristaltic pump at constant speed?2083 ?L / min?.At the time of 60,90,120,150 and 180 minutes after the start of perfusion,the breath was collected,the 13CO2 concentration in the exhaled gas was measured and the ¹³C-Phe oxidation rate was calculated.Analyze the rate of ¹³C-Phe oxidation in different Arg gradient exhalation by the covariance analysis.According to the Arg perfusion and ¹³C-Phe oxidation rate variables for non-linear regression analysis to determine the inflection point,the inflection point is Arg requirements.The results showed that the yield of ¹³C-Phe oxidation ranged from 33.2-37.6 % with the increase of Arg intake.The rate of ¹³C-Phe oxidation was related to the change of Arg intake?P<0.05?without being affected by body weight?P= 0.103?.With the increase of Arg intake from 2.39 to 7.84 g/d,the rate of ¹³C-Phe oxidation was significantly decreased?P<0.05?,and the rate of occurrence of Arco intake was not changed?P> 0.05?.Comprehensive assessment of Kazak growth lambs Arg requirements to an average of 7.84 g/d.The results showed that Arg had a limiting effect on Kazakh sheep under the actual feeding conditions,and the minimum physiological requirement of Arg was 7.84 g/d.The results of this study provide a reasonable basis for the rational addition of rumen-protected arginine in the future,and provide the experimental basis for the optimal design of AA balanced diet of small intestine.