Spatial-temporal Patterns Of Amino Acid Content In Staple Food Bamboo (Bashania Fargesii) Of Giant Panda (Ailuropoda Melanoleuca) In Foping Reserve

Amino acid plays a supporting role in animal nutrition.The Giant Panda(Ailuropoda melanoleuca)feed on low protein and high fiber bamboo have a series of adaptive strategies.Content of 18 kinds of conventional amino acids in bamboo(Bashania fargesii)leaves at different bamboo ages(1-year old,2-year old and perennial)and different months(January to December)in Foping Nature Reserve at an altitude of 1200 m ~ 1900 m,were detected by an Automatic Amino Acid Analyzer(Sykam S433D).The spatial-temporal variation of amino acid content in bamboo leaves was analyzed.According to the activities of giant pandas in this area,Total Amino Acids(TAA),Total Essential Amino Acids(TEAA),Total Non-essential Amino Acids(TNEAA)and 18 kinds of amino acids in bamboo leaves in leaf eaten season and non-leaf eaten season,in giant panda core habitat area and marginal habitat area,were compared.1.Temporal and spatial changes of amino acid content in bamboo leavesThe content of amino acid in bamboo leaves was significantly affected by month and season.TEAA,TNEAA and TAA content in Bashania fargesii leaves in autumn and winter were significantly higher than that in spring and summer(P<0.01).Among all the essential amino acids,leucine(Leu)has the highest content,methionine(Met)has the lowest content.Content of essential amino acids in autumn and winter was higher than that in spring and summer,but the content of cysteine(Cys)in autumn was the lowest among seasons.Content of glutamate(Glu)and aspartic(Asp)was higher among all the non-essential amino acids.Content of each non-essential amino acid in autumn and winter was higher than that in spring and summer,but the aspartic(Asp)was the lowest among seasons.Bamboo age had significant effect on amino acid content in Bashania fargesii leaves.18 kinds of essential amino acids content in different bamboo ages act as: 1-year leaf > 2-year leaf > perennial leaf.Cysteine(Cys)content has no significant difference between ages,while glutamate(Glu)and aspartic(Asp)just on the contrary.The remaining 15 kinds of amino acids were significantly higher in 1-year bamboo leaves than that in 2-year leaves and perennial leaves(P<0.01),but no significant difference between 2-year leaves and perennial leaves.There was no significant difference in TEAA,TNEAA and TAA content of 1-and 2-year leaves among different elevations.TAA content in perennial leaves at an altitude of 1400 m was significantly higher than which at an altitude of 1600 m.Content of Thr,Tyr and His in perennial leaves were significantly higher at the altitude of 1400 m than 1600 m.Content of serine(Ser)in perennial leaves was significantly higher at 1400 m than 1500 m,1600 m and 1900 m.Content of alanine(Ala)was significantly higher at 1400 m than 1600 m and 1900 m,and TNEAA content was significantly higher at 1400 m than 1500 m and 1900 m.2.Comparison of amino acid contents in bamboo leaves in giant panda leaf eaten season and non-leaf eaten seasonContent of TAA(12.33±1.74%),TEAA(5.14±0.85%)and TNEAA(7.20±0.94%)in bamboo leaves were much higher in the leaf eaten season than that in the non-leaf eaten season(10.39±1.45%,4.23±0.67%,6.61±0.82%)(P<0.01).Content of asparagine(Asp)and cysteine(Cys)were significantly lower in leaf eaten season than which in non-leaf eaten season(P<0.01),the remaining 16 amino acids content were significantly higher in leaf eaten season than which in non-leaf eaten season(P<0.01).3.Comparison of amino acid contents in bamboo leaves in giant panda core and marginal habitat areasIn the leaf eaten season,TAA content in bamboo leaves in the core habitat area(12.55±1.60%)was significantly higher than that in the marginal habitat area(11.87±1.68%)(P<0.05),and TNEAA content(7.33±0.89%)was extremely significantly higher than that in the marginal habitat area(6.92±0.89%)(P<0.01).TEAA content in bamboo leaves in the core habitat area was higher than that in the marginal habitat area,but the difference was not significant.Contents of Thr,Glu,Ala and Tyr in bamboo leaves in the core habitat area of giant panda in leaf eaten season were significantly higher than those in the marginal habitat area(P<0.05),and the contents of Ser,His and Pro were significantly higher than those in the marginal habitat area(P<0.01).4.ConclusionContent of amino acid in Bashania fargesii leaves in Foping Nature Reserve was affected by month,altitude and bamboo ages.In giant panda leaf-eaten season,content of TAA,TEAA and TNEAA were significantly higher than that in giant panda non-leaf-eaten season.The active selection behavior of giant panda allows giant pandas to obtain higher content of amino acids from staple bamboo food.At the same time,in giant panda leaf-eaten season,bamboo which grow in the giant panda core habitat area contain higher TAA and TNEAA,and contain higher threonine(Thr),glutamate(Glu),alanine(Ala),tyrosine(Tyr),serine(Ser),histidine(His)and proline(Pro).Functions of these amino acids inside animal's body may consistent with specific physiological characteristics of giant pandas.Such as: Content of glutamic is the highest in giant panda tissues.Alanine and its effect of relieving bitterness may be helpful to reduce the bitterness test of tannic acid in bamboo.These results may be one of the factors that promoting giant panda optimizing its foraging strategies.This study will contribute to a comprehensive understanding of the temporal and spatial variation of amino acids in bamboo,and helpful for further depth studying of the influencing factors of habitat selection of giant panda based on bamboo nutrition.At the same time,it can provide a reference for captive giant panda amino acid requirement.