日粮粗纤维水平对莱芜猪及其杂交猪氮代谢及营养物质消化率的影响

采用全收粪尿和回肠瘘管法研究了日粮粗纤维水平和不同杂交组合猪对氮代谢和回肠末端营养物质表观消化率的影响。采用二因子二水平有重复设计,选用4月龄莱芜猪及其杂交猪,饲喂不同粗纤维含量(3%、6%、9%、12%)的日粮。日粮纤维水平对食入氮(IN)、粪氮(FN)、消化氮(DN)、沉积氮(RN)、氮表观消化率影响极显著(P<0.01),对尿氮(UN)影响显著(P<0.05);杂交组合对IN、FN、DN、RN、ABV影响极显著(P<0.01)。日粮纤维在较低水平(3%~6%),CP消化率随粗纤维含量增加而提高,随粗纤维含量增加(6%~12%),营养物质消化率显著降低(P<0.05);杂交组合对干物质、CP、钙(Ca)、磷(P)消化率影响极显著(P<0.01),莱芜猪对中性洗涤纤维(NDF)的消化率为51.44%,大约克猪为43.51%,差异显著(P<0.05);NDF和酸性洗涤纤维(ADF)表观消化率随试验猪含莱芜猪血统比例的降低而显著降低;日粮纤维在3%~6%范围内,除赖氨酸、蛋外的必需氨基酸(EAA)随日粮纤维水平的增加显著降低;杂交组合对EAA表观消化率除赖氨酸、苏氨酸、异亮氨酸外均不显著(P>0.05)。日粮纤维对猪营养物质的消化吸收具有正负两方面的效应,杂交组合对氮利用率和粗纤维的消化分解率不同。

INFLUENCE OF CRUDE FIBER LEVELS AND PIG BREEDS ON NITROGEN METABOLISM AND ILEAL APPARENT DIGESTIBILITY

An experiment was conducted to evaluate the influence of dietary crud fiber levels and breeds on nitrogen metabolism and ileal apparent digestibility.Laiwu Pigs and crossbreeds of Laiwu and Yorkshire,four months old,were used as experiment animals.The diets had different levels of crud fiber(CF)(3%、6%、9%、12%).Dietary CF levels had significant influence on intake nitrogen(IN),faeces nitrogen(FN),digestive nitrogen(DN),retained nitrogen(RN),N apparent digestibility(P<0.01) and urine nitrogen(UN)(P<0.05).Breeds had significant influence on IN,FN,DN,RN and ABV(P<0.01).Analysis of ileal digestibility indicated that when dietary CF was at lower levels(ranged from 3%-6%),digestibility of CP increased with the increase of CF levels.Whereas,when the CF level was at higher levels(ranged from 6%-12%),digestibility of nutrient was decreased significantly(P<0.05).Breeds had significant influence on the digestibility of dry matter,CP,calcium(Ca) and phosphorus(P)(P<0.05).The digestibility of NDF of Laiwu and Yorkshire pig was 51.44% and 43.51%(P<0.05),respectively.The apparent digestibility of NDF and ADF of all experiment pigs was significantly decreased with the decrease of ancestral descent of Laiwu pigs.NDF can be digested in the small intestine effectively.When dietary CF was at high levels,ranged from 3% to 6%,the apparent digestibility of lysine and methionine had no significantly different(P>0.05),while that of other essential amino acid(EAA) decreased significantly with the increase of CF levels.Except for lysine,threonine and isoleucine,all the other EAA’s apparent digestibility had no significant different among the different breeds(P>0.05).The dietary CF has dual effect on the digestion and absorption of nutrient,Different breeds have different N and CF digestibility and NDF had been digested in the small intestine effectively.