Investigations Of Requirements Of Intestinal Metabolisable Met And Lys For Growing-fattening Lamb By IAAO Technique

The aim of this study was to use the indicator amino acid oxidation technology?IAAOT?with(¹³C-Phe)as an indicator of the amino acid,to discuss the Kazak sheep in the routine feeding conditions on Met and Lys requirements,so as to improve the utilization of nitrogen in Kazak sheep and nitrogen deposition.Experiment 1 : In order to investigate the fattening sheep under the condition of feeding jugular vein infusion ¹³C-phenylalanine(¹³C-Phe)as an indicator of amino acid metabolism kinetics of amino acids,the exhaled ¹³CO2 isotopic abundance of time to reach steady state and plateau duration.Select 4 weighing about 32 kg Kazakh lambs as test animals,the metabolic cage caged.Daily at 90%?1 200 g?were fed a normal intake of 2 times.The first to sixth days of adaptation,the first seven days of infusion and sampling of exhaled.Acquisition infusion process to perfusion exhaled sample at different time points after the measured 13 C micrometer difference to determine isotopic steady state.The results showed that four test in sheep fed conditions as the instructions ¹³C-phenylalanine amino acid IAAO measured exhaled micrometer sample 13 C difference increased rapidly after the infusion began,the platform can be maintained of 2 h,and ultimately determine the optimum sampling time ¹³C-phenylalanine is after the start of perfusion of the 1.5 4 h.The results of this study for the future determination of animal protein and various amino acid requirements of the foundation.Experiment 2: The objective of this experiment was to estimate the duodenal supplemental requirement of Met using the indicator amino acid oxidation?IAAO?method.Three Kazakh lambs?32 kg?with duodenal cannulae housed in individual with The indicator amino acid oxidation?IAAO?method is based on the concept that when the most limiting amino acid?LAA?is deficient for protein synthesis,then all other AA will be oxidized.With increasing intakes of the LAA,IAAO will decrease until the requirement for the LAA is met and no further change in the indicator oxidation afterwards.Therefore,the catabolism of ¹³C-Phe was used to indicate the effects of varying duodenal infusing level of Met on the oxidation rate by 4-month-old Kazakh lambs?30.8 ± 0.4 kg BW?.After a 6-d adaptation period,the IAAO test was conducted on d 7.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 NaH¹³CO3 at time 0.Then the constant infusions [1.33 mg ¹³C-Phe /?kg·h?-1] were started.Breath samples were collected prior to and half-hourly between 90 and 210 min after the start of the ¹³C-Phe infusions.An estimate of the mean Met requirement was determined by breakpoint analysis of the rate of ¹³CO2 released by ¹³C-Phe oxidation with a 2-phase linear regression model.The oxidation rate of ¹³C-Phe decreased?P < 0.001?with increasing amounts of methionine infused in a dose dependent fashion up to 1.65 g/day and was not different from 1.65 to 2.15 g/day?P > 0.05?.The mean Met requirement was estimated to be 1.28 ± 0.11 g/day of supplementation.The total postruminal minimum requirement of Met would be 2.02 g/day when the basal passage of Met?0.74 g/day?was summed.Experiment 3: The objective of this experiment was to estimate the duodenal supplemental requirement of Lys using the indicator amino acid oxidation?IAAO?method.Three Kazakh lambs?initial BW 42.5 ± 0.4 kg at six-month age?with duodenal cannulae housed in individual metabolic crates were restrict fed twice daily in equal parts?550 g?of the diet to avoid from orts.A series of five infusion and IAAOT was conducted in which the lambs were made limiting only in Lys by the duodenal infusion of a mixture the amino acids devoid of Lys.This limitation was sequentially removed in subsequent trials by the duodenal infusion of graded amounts of Lys.After a 6 days adaptation to the basal experimental diet and to daily infusion treatment,the IAAOT was conducted on 7 day.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-sodium bicarbonate at time 0.Then the constant infusions?1.33 mg/h·kg BW?were started using variable speed syringe pumps.Exhaled samples were collected at min 90,150 and 210 with an interval of 60 min.Expired ¹³CO2 enrichment was measured by a continuous flow isotope ratio mass spectrometer and the rate of ¹³CO2 released by ¹³C-Phe oxidation(?mol ¹³C·kg-1·h-1)is calculated.Estimates of the mean Lys requirement were derived by breakpoint analysis of the rate of phenylalanine oxidation with a two-phase linear regression crossover model.The oxidation rate decreased linearly?P < 0.001?and in a dose dependent fashion up to 2.94 g/day and was not different from 4.54 to 6.14 g/day?P > 0.05?.The postruminal minimum Lys requirement varied from 6.09 to 6.92 g/day for individual lambs.The mean Lys requirement for the lambs was estimated to be 2.92 ± 0.47 g/day of supplementation.Thus,the total postruminal minimum requirement of Lys would be 6.38 g/day when the basal passage of Lys?3.46 g/day?was summed.The research indicates that the minimum Met and Lys of the Kazakh lamb requirement of 2.02g/d and 6.38g/d using IAAOT,the results for fattening lamb diet AA balance provided a favorable basis.