Effect of graded levels of fiber from alfalfa meal on apparent and standardized ileal digestibility of amino acids of growing pigs

Two experiments were conducted to determine the effects of fiber level from alfalfa meal and sampling time on the apparent ileal digestibility（AID） and standardized ileal digestibility（SID） of amino acids（AA） in growing pigs. A total of 24 ileal-cannulated pigs（Duroc×（Large White×Landrace） with body weight（21.4±1.5） kg） were randomly allotted to 4 treatments. The pigs were provided a corn-soybean meal diet or a diet containing 5, 10 or 20% of alfalfa meal during two 10-d experimental periods. The AID of AA was measured. Six ileal-cannulated pigs were fed a protein-free diet in order to estimate the endogenous protein losses and SID of AA. Ileal AA digestibility was not affected by inclusion of 5 or 10% alfalfa meal in the diet（P〉0.05）. The AID of His, Lys, Met, Phe, Thr, Val, Ala, Asp, Cys, Gly, Pro, Ser and Tyr reduced by 2.0–6.8% with the addition level of alfalfa meal（linear, P〈0.05）. The SID of His, Lys, Ser, Thr and Tyr decreased by 2.2–4.3% as the level of alfalfa meal in the diet increased（linear, P〈0.05）. The AID and SID of AA were not affected by the sampling time（P〉0.05）. A multiple linear regression analysis, taking into account both the soluble and insoluble fiber content in the diets, explained more than 36% of variation in SID of Ser and Thr（P〈0.05）. In conclusion, the corn-soybean meal diet containing 10% of alfalfa meal did not affect ileal AA digestion. The AID and SID of AA were similar between two sampling times. Increasing the concentration of total dietary fiber from 12.3 to 21.4% by adding graded levels of alfalfa meal（0–20%） to a corn-soybean meal control diet induced a linear reduction in AID and SID of most AA. Soluble and insoluble fibers from alfalfa meal have differential roles in the AA digestion, which may help explain the variation observed in the SID of partial AA. These findings would provide important information for dietary fiber level and composition related to AA digestion.

Determination of the available energy values and amino acid digestibility of Flammulina velutipes stem waste and its effects on carcass trait and meat quality fed to growing-finishing pigs

Background:Flammulina velutipes stem waste(FVS)is the by-product of mushroom industry.The objectives of this study were to determine the available energy and amino acid digestibility of FVS fed to pigs,and to evaluate the effects of dietary FVS inclusion on growth performance,biochemical profile of serum,fecal short chain fatty acid(SCFA)concentration,carcass traits,meat quality,intestinal morphology and microflora of pigs.In Exp.1,twelve crossbred barrows with initial body weight(IBW)of 37.48±4.31 kg were randomly allotted to 2 dietary treatments,including a corn basal diet and an experimental diet containing 24.35%FVS.In Exp.2,twelve barrows fitted with an ileal T-cannula(IBW:32.56±1.67 kg)were randomly allotted to 2 dietary treatments,which included a N-free diet and an experimental diet containing 40.0%FVS.In Exp.3,ninety growing pigs(IBW:63.98±6.89 kg)were allotted to 1 of 3 treatment diets for 63 d,including a basal diet and 2 experimental diets with 2.5%and 5%FVS,respectively.Results:The digestible energy(DE)and metabolizable energy(ME)of FVS were 4.58 and 4.06 MJ/kg on dry matter basis,respectively,and the standardized ileal digestibility(SID)of indispensable AAs ranged from 17.50%to 59.47%.Pigs fed diets with 2.5%FVS showed no difference on average daily gain(ADG)and gain to feed ratio(G/F).Although dietary 5%FVS inclusion impaired apparent total tract digestibility(ATTD)of organic matter and gross energy,it elevated the SCFA concentration(P≤0.04)in gut and antioxidant capacity in serum.In addition,dietary FVS inclusion depressed the backfat thickness(P=0.03)in pigs.The longissimus dorsi muscle of pigs fed FVS revealed higher n-3 polyunsaturated fatty acid concentration and optimized fatty acid composition.Dietary 2.5%FVS inclusion also improved the intestinal development and health by increasing the villius height to crypt depth ratio(V/C)in jejunum(P<0.01),and promoting microbial diversity and beneficial microbiota proliferation.Conclusions:It is feasible to include moderate content of FVS as an unconventional fiber ingredient in diet of growingfinishing pigs.

日粮纤维水平对猪营养物质表观消化率的影响

为了测定日粮不同纤维水平和品种对猪营养成分表观消化率的影响,试验选用8头4月龄猪,采用4×4拉丁方设计进行试验。4种试验日粮按等能等氮设计,日粮Ⅰ、Ⅱ、Ⅲ、Ⅳ粗纤维水平分别为3%、6%、9%和12%（干物质基础）,4个品种分别为莱芜猪（100%）、大莱猪（50%）、大大莱猪（25%）、大约克猪（0%）。在本试验条件下,日粮纤维在较低的范围内（3%~6%）粗蛋白质（CP）消化率随粗纤维含量的增加而提高,赖氨酸、蛋氨酸表观消化率差异不显著,CP在粗纤维含量6%时,消化率最高达到86.90%。不同品种猪对干物质、Ca、P的消化率影响极显著（P〈0.01）,但莱芜猪和大约克猪对干物质、CP消化率的影响差异不显著,莱芜猪对NDF的消化率为51.44%,大约克猪为43.51%,两者之间差异极显著（P〈0.01）。NDF和ADF的表观消化率随猪血统中莱芜猪血比例的降低而显著降低,NDF在小肠中已得到有效的分解,本试验结果证实莱芜黑猪具有耐粗饲的特性。不同品种猪对必需氨基酸（EAA）的表观消化率除赖氨酸、苏氨酸、异亮氨酸外影响均不显著。

日粮中添加丁酸梭菌对猪氨基酸全肠道表观消化率及血脂组成的影响

旨在探讨不同日粮蛋白质水平条件下,添加丁酸梭菌对生长猪粗蛋白质和氨基酸全肠道表观消化率、氮平衡、血液脂肪酸组成及血液生化指标的影响。试验选用24头初始体重为(39.07±1.80)kg的健康杜×长×大三元杂交去势公猪,按照随机区组分为4组,每组6个重复,每个重复1头猪。采用2×2因子设计,共设日粮丁酸梭菌添加水平(0、100mg·kg-1)和日粮粗蛋白质水平(14%、18%)两个因子,试验预试期6d,正试期13d,于试验最后3d全收粪法收集粪样和尿样,最后1d采集每头猪的血样。结果表明,日粮中添加丁酸梭菌显著降低了生长猪蛋氨酸的全肠道表观消化率(P<0.05),显著提高了血清中顺式-5,8,11,14,17-二十碳五烯酸含量(P<0.05)。与常规蛋白质水平组相比,低蛋白质水平组猪尿氮排放显著降低、氮的利用率显著升高(P<0.05),除了蛋氨酸、色氨酸的全肠道表观消化率显著增加(P<0.05)外,精氨酸、组氨酸等多数氨基酸的消化率均显著降低(P<0.05),亚油酸含量显著降低(P<0.05)。丁酸梭菌与日粮蛋白质水平的互作效应对生长猪血清中总脂肪酸、二十四酸、棕榈油酸和花生四烯酸含量的影响显著(P<0.05)。本研究表明,丁酸梭菌降低了日粮中蛋氨酸全肠道表观消化率,但能提高血清中顺式-5,8,11,14,17-二十碳五烯酸含量,且丁酸梭菌和日粮蛋白质水平对血清中总脂肪酸、二十四酸、棕榈油酸、花生四烯酸含量互作显著。

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。

饲粮中添加苜蓿草粉对生长猪结肠微生物区系及其代谢产物的影响

本试验旨在研究苜蓿草粉来源的不可溶性纤维对生长猪结肠微生物区系及其发酵代谢产物的影响。试验选用24头(24.8±0.7)kg的杜×长×大去势公猪,随机分为4组,分别饲喂含0(对照组)、5%、10%和15%苜蓿草粉的饲粮,每组6个重复,每个重复1头猪。试验28 d后屠宰取样,测定血清脂肪酸组成、结肠食糜短链脂肪酸浓度及微生物组成。结果发现:饲喂苜蓿草粉显著降低了生长猪的料重比(P<0.05),但对平均日增重和平均日采食量无显著影响(P>0.05);结肠微生物菌群16S r DNA V3区测序结果表明,苜蓿草粉对猪结肠微生物区系无显著影响(P>0.05),但显著增加了结肠食糜中总短链脂肪酸、乙酸和丁酸的浓度(P<0.05);随着饲粮中苜蓿草粉含量的增加,血清多不饱和脂肪酸含量显著提高(P<0.05),而饱和脂肪酸和单不饱和脂肪酸含量显著下降(P<0.05)。结果提示:苜蓿草粉来源的不可溶性纤维不影响结肠微生物菌群结构,但增强了结肠微生物的发酵活动和短链脂肪酸的产生,具有调节猪机体脂肪酸组成的作用。