Effects Of Dietary Arginine On The Performances Of Heat Stress Pekin Ducks In Summer

The curre nt intensive indoor produce syste m le ads to commercialPekin duc ks never to have adequate water for swimming or wetting theirbodies， therefore heat stress is becomi ng a key factor infl uencing healthand growt h of ducks， especially in the hot region and sea son．Experi me nt1was conduct ed to study whether heat-stress wasdeleterious to ducks， and to give a support to the Experiment2． Fortyone-day-old male and fe male Pekin ducks were randomly allocated to4electrically heated battery brooders of10ducks． Ducks were exposed t osuddenly37℃ambient temperature for3h，and then slaughtered，in onebrooder at21d and in another brooder a t49d of age， respectively．The result showed that acute high-temperature let ducks compared withthe control:(1) to increase the rectal temperature and respiratory rate (P<0.05)，to suffer from heat stress．(2) to improve the serum enzyme activities of ALT and AST， thelevel of serum BUN (P<0.05)，to reduce the serum enzyme activity of ALP(P<0.05)．(3) to enhance WBC， neutr ophils and basophi ls cell contents， H/Lratio (P<0.05)， t o decrease monoc yte and lymphatic cell contents(P<0.05)．(4) to have the trend to decrease body weight (P>0.05)；t o reduce theorgan indexes of li ver， spleen， thymus and bur sa of Fa bricius (P<0.05)．(5) to reduced villus heights， V/C ratios and villus surface areas(P<0.05) and to e nlarge crypt depths and villus widths (P<0.05) o fduodenum， ileum a nd jejunum．Experi me nt2was carried out to inves tigate the influence of dietary L-arginine (Arg) supple ment on the perfor manc e of Peki n ducks， undernatural temperature environment of Wuhan fr om July to August．150one-day-old unsexed Pekin ducks were randomly divided into3treatment s fed expe rimental diets supple mented with0%，0.5%，and1.0%L-Arg， r espectively． The trial lasted7wk．The result showed t hat the addition of L-Arg could：(1) have no effects on ADFI，ADG and F/G of ducks from0to21d ofage (P>0.05)； have a tende ncy to inc rease ADFI and ADG， to decreaseF/G of ducks from22to49d of age (P>0.05)； reduce F/G (P<0.05) in0.5%L-Arg treatme nt during the period of trial．(2) decrease the serum enzyme activities of ALT and AST， the levelof BUN (P<0.05)，increase the serum enzyme activity of ALP (P<0.05) in0.5%L-Arg treatme nt at21d and49d of age．(3) reduce WBC， neutr ophils and basophi ls cell content， H/L ratio(P<0.05)，to increase monoc yte，lymphatic and eosinophilic cell contents(P<0.05) at21d and49d of age．(4) i mproved the liver index (P<0.05) and have a tendency to enlargethe indexes of thymus and bursa of fa bricius (P>0.05) at21d of age．(5) improve vi llus height and V/C ratio (P<0.05)，reduce crypt depth(P<0.05) of duodenum， jejunum and i leum， enhance villus surface area(P<0.05) of jejunum and ile um in0.5%L-Arg t reatment49d of age．(6) have no e ffects on body weight， slaughter rate， percentage ofeviscerated yield，semi-eviscerated yield，leg muscle rate，breast musclerate， and sebum ra te (P>0.05)， have a tendency to reduce abdominal fa trate (P>0.05) at49d of a ge．(7) gradually decrease (P<0.05) the hepatic water content andincrease the hepatic protein content (P<0.05) with the increasing dietaryL-Arg at49d of age． In conclusion， acute heat stress was har mful to the perfor ma nces ofducks，and it changed serum enzyme activity，WBC and differential whiteblood count，as well as it shrink body weight，i mmune orga ns such as liverand intestinal mucous villus； Dietary0.5%L-Arg s upple ment couldreduce F/G during the period of7wk in Pekin ducks unde r high a mbienttemperature in summer， which might attribute to the beneficial hepaticand intestinal mucous change s．...