川中丘陵地区不同生长高度巨菌草的营养成分比较分析

Comparative Analysis of Nutritional Components of Pennisetum giganteum at Different Growth Heights in Hill Regions of Central Sichuan

为研究川中丘陵地区不同生长高度巨菌草(Pennisetum giganteum)的营养成分变化规律,对生长高度分别为50~100 cm、100~150 cm、150~200 cm、200~250 cm的巨菌草取样,测定其常规营养成分、维生素、氨基酸以及单宁含量。结果显示:巨菌草的干物质、粗灰分、粗纤维、酸性洗涤纤维、酸性洗涤木质素含量随生长高度的增加极显著增加(P<0.01),总能和中性洗涤纤维含量随生长高度的增加而显著增加(P<0.05),粗蛋白质含量则随生长高度的增加极显著下降(P<0.01)。150~200 cm和200~250 cm巨菌草的粗脂肪含量显著高于50~100 cm和100~150 cm巨菌草(P<0.05)。不同生长高度的巨菌草钙、总磷含量差异不显著(P>0.05)。巨菌草的第一限制性氨基酸为异亮氨酸,必需氨基酸、非必需氨基酸以及总氨基酸含量随巨菌草生长高度的增加而下降,以50~100 cm巨菌草最高,并且极显著高于其他生长高度巨菌草(P<0.01);50~100 cm巨菌草的(甜味氨基酸+酸鲜味氨基酸)/苦味氨基酸值最高。必需氨基酸/非必需氨基酸、必需氨基酸/总氨基酸、必需氨基酸/粗蛋白质值随巨菌草生长高度的增加而降低。β-胡萝卜素、维生素C、维生素B 6含量随巨菌草生长高度的增加而增加。单宁含量随巨菌草生长高度的增加而降低。本研究结果表明,川中丘陵地区巨菌草与其他地区巨菌草的部分营养成分变化规律不同。单胃动物宜选择生长高度100 cm以下的巨菌草,反刍动物选择生长高度100 cm以上的巨菌草较适宜。

In order to investigate the change rule of Pennisetum giganteum at different growth heights in the hill regions of central Sichuan,the contents of conventional nutritional components,vitamins,amino acids and tanin of Pennisetum giganteum at the growth heights of 50 to 100 cm,100 to 150 cm,150 to 200 cm and 200 to 250 cm were evaluated,respectively.The results showed that the contents of dry matter(DM),ash(Ash),crude fiber(CF),acid detergent fiber(ADF)and acid detergent lignin(ADL)of Pennisetum giganteum were extremely significantly increased with the growth height increasing(P<0.01),and the general energy(GE)and neutral detergent fiber(NDF)content were significantly increased with the growth height increasing(P<0.05).However,the content of crude protein(CP)of Pennisetum giganteum was extremely significantly decreased with the growth height increasing(P<0.01).Meanwhile,the contents of ether extract(EE)of 150 to 200 cm and 200 to 250 cm Pennisetum giganteum was significantly higher than that of 50 to 100 cm and 100 to 150 cm Pennisetum giganteum(P<0.05),whereas no significant differences were observed in the contents of calcium(Ca)and total phosphorus(TP)of Pennisetum giganteum among different growth heights(P>0.05).Furthermore,isoleucine(Ile)was the first limiting amino acid of the Pennisetum giganteum.The contents of essential amino acids(EAA),non-essential amino acids(NEAA)and total amino acids(TAA)of Pennisetum giganteum were decreased with the growth height increasing,and 50 to 100 cm Pennisetum giganteum had the highest values,which were extremely significantly higher than that of Pennisetum giganteum at other growth heights(P<0.01).The highest ratio of sweet taste amino acids plus fresh taste amino acids to bitter taste amino acids was also observed in the 50 to 100 cm Pennisetum giganteum,while the ratios of EAA/NEAA,EAA/TAA and EAA/CP of Pennisetum giganteum were decreased with the growth height increasing.Moreover,the contents ofβ-carotene,vitamin C and vitamin B 6 of Pennisetum giganteum were increased with the growth height increasing,whereas the content of tannin was decreased with the growth height increasing.The results of this research indicate that some nutritional components of the Pennisetum giganteum grown in the hill regions of central Sichuan are different from those of the Pennisetum giganteum in the other regions.Pennisetum giganteum with a<100 cm growth height is suitable to be used for monogastrics,whereas ruminants are better to be fed the Pennisetum giganteum with a>100 cm growth height.