Organic matter and macromineral digestibility in domestic rabbits (Oryctolagus cuniculus) as compared to other hindgut fermenters

It is generally assumed that animal species differ in physiological characteristics of their digestive tract. Because investigating digestive processes is often labour‐intensive, requiring lengthy adaptation and collection periods, comparisons are often made on the basis of data collated from different studies. We added a new data set on dietary crude fibre (CF) and macromineral (Na, K, Ca, P, Mg) composition and apparent digestibility (aD) of organic matter (OM) and macrominerals in rabbits (Oryctolagus cuniculus; a total of 180 measurements with 12 individuals and 10 different diets) to a literature data collection for rodents and domestic horses (Equus caballus). Significant negative relationships between dietary CF and aD OM were obtained, but the significant difference in digestive efficiency between rabbits and guinea pigs (Cavia porcellus) reported from studies where both species had been investigated under identical conditions were not detectable in the larger data collection. However, the 95% confidence interval of the negative slope of the CF–aD OM relationship did not overlap between domestic horses on the one hand, and rabbits and guinea pigs on the other hand, indicating a less depressing effect of CF in horses. Akaike's information criterion indicated that aD of a macromineral did not only depend on its concentration in the diet, but also on the individual and various other diet characteristics and the presence of other macrominerals, indicating complex interactions. The data indicate similar mechanisms in the absorption of macrominerals amongst rabbits, rodents and horses, with the exception of Na and K in guinea pigs and Ca in chinchillas (Chinchilla laniger) that should be further corroborated. In particular, the occurrence of high aD Ca in hindgut fermenters, regardless of whether they employ a digestive strategy of coprophagy or whether they have fossorial habits, suggests that this peculiarity might represent an adaptation to hindgut fermentation in general.     

Intake, selection, digesta retention, digestion and gut fill of two coprophageous species, rabbits (Oryctolagus cuniculus) and guinea pigs (Cavia porcellus), on a hay-only diet

A colonic separation mechanism (CSM) is the prerequisite for the digestive strategy of coprophagy. Two different CSM are known in small herbivores, the 'wash-back' CSM of lagomorphs and the 'mucous-trap' CSM of rodents. Differences between these groups in their digestive pattern when fed exclusively hay were investigated in six rabbits (Oryctolagus cuniculus) and six guinea pigs (Cavia porcellus). Intake, digestibility (by total faecal collection), solute and particle mean retention times (MRT, using Co-EDTA and Cr-mordanted fibres) were measured. Rabbits selected less fibrous parts of the hay than guinea pigs, leaving orts with higher content of neutral detergent fibre [NDF; 721 ± 21 vs. 642 ± 31 g/kg dry matter (DM) in guinea pigs]. They also expressed a lower NDF digestibility (0.44 ± 0.10 vs. 0.55 ± 0.05 of total), a similar particle MRT (15 ± 3 vs. 18 ± 6 h), a longer solute MRT (51 ± 9 vs. 16 ± 4 h), and a lower calculated dry matter gut fill (19.6 ± 4.7 vs. 29.7 ± 4.1 g DM/kg body mass) than guinea pigs (p < 0.05 for each variable). These results support the assumption that the 'wash-back' CSM, exhibited in the rabbits, is more efficient in extracting bacterial matter from the colonic digesta plug than the 'mucous-trap' CSM found in the guinea pigs. Related to metabolic body mass, rabbits therefore need a less capacious colon for their CSM where a more efficient bacteria wash-out is reflected in the lower fibre digestibility. A lighter digestive tract could contribute to a peculiarity of lagomorphs: their ability to run faster than other similar-sized mammals.     

Digestive enzyme activities of pancreas and intestinal digesta in streptozotocin-induced diabetic piglets

Six (Landrace × Large White) × Duroc crossbred, castrated weanling piglets were used to evaluate the effect of a streptozotocin (STZ) injection to induce diabetes on the activities of digestive enzymes derived from the pancreas (lipase, amylase, trypsin and chymotrypsin) in the pancreas and intestinal digesta. Fasting plasma glucose after the administration of STZ was maintained at the level of 302–491 mg/dL during this experiment, compared with the level of 89–125 mg/dL in the control group, and they were defined as the STZ‐induced diabetic piglets for about 7 weeks. Although their bodyweight increased in proportion to a quadratic curve (P < 0.0001) during 49 days after the administration of STZ, the growth of the STZ‐induced diabetic piglets was slower compared with the control. The STZ‐injection did not affect the percentage of the pancreas in bodyweight. The administration of STZ in the piglets tended to accelerate the activity of lipase (P = 0.06) and depress the activity of amylase (P = 0.15) or chymotrypsin (P = 0.18), as units/kg bodyweight, in the pancreas. In the case of measurement as units/kg bodyweight, the activities of intestinal digesta in the STZ group showed a tendency to be higher than those in control group, irrespective of the sort of enzymes. In conclusion, STZ‐induced diabetic piglets have a moderate digestive ability and the administration of exogenous digestive enzymes is not necessary when they are used as a diabetic animal model.     

非同位素双标记法测定十二指肠、回肠食糜流量方法的研究

以4只安装有永久性瘤胃瘘管、十二指肠、回肠瘘管的小尾寒羊阉公羊为试验动物。采用 Cr2O3、聚乙二醇(PEG)为非同位素双标记法的食糜和食糜液相标记物,分别对于连续饲喂条件下标记物的回收率、标记物浓度达到平衡的时间、食糜流量的稳定性及标记物的瘤胃平均滞留时间等进行了研究。结果表明:Cr2O3、PEG平均回收率分别为95.75%±20 63%、91.48%±12.63%。全食糜和食糜液相中的标记物Cr2O3、PEG浓度在4 d内基本达到了平衡。由标记物 Cr2O3、PEG 利用双标记法测定的十二指肠、回肠平均食糜流量分别为 10 054 3±1.726 5 L/d、5.629 5±0 901 9 L/d,其变异系数分别为0 171 7、0 116 0,测定结果具有较好的稳定性和可靠性。标记物Cr2O3、PEG 的瘤胃平均滞留时间分别为 88、40 h。其浓度随时间的递降曲线分别为: Cr2O3: y =0 38e-0 039 7t(r=0 975 0);PEG:y=0 367e-0 098 12t(r=0 868 5)。     

生长猪回肠末端瘘管中食糜养分流量及指示剂回收率的变异

食糜样品的代表性是研究养分在猪体内消化过程的关键。通过T型瘘管获得的代表性食糜采样方案必须基于瘘管中食糜养分的流量及指示剂的回收率。本试验以4头在回肠末端安装瘘管的生长猪[(21.3±1.0)kg]为试验对象,饲喂玉米-豆粕型饲粮。采用3×16双因素完全随机设计,其中采样日设3个水平,即试验期第8、9、10天。日内采样时间设16个水平,即08:00~24:00,每小时通过瘘管采集1次回肠食糜样品,记录鲜食糜的重量并分析食糜样品中总能,干物质、粗蛋白质及三氧化二铬的含量。研究结果如下:1)双因素方差分析表明,日内采样时间显著地影响了瘘管中食糜的鲜食糜、干物质、总能、粗蛋白质和三氧化二铬的流量(P<0.05);在采样日间,瘘管中食糜的鲜食糜、干物质、粗蛋白质和三氧化二铬的日内平均流量均无显著性差异(P>0.05),但回肠末端食糜的总能流量有显著性差异(P<0.05)。2)日内16 h累计流经回肠瘘管的食糜及全天流经回肠末端的食糜在干物质、总能、粗蛋白质总流量的日间变异上有显著性差异(P<0.05),其中试验期第8天的流量均显著地高于第9、10天的相应值(P<0.05),而第9、10天间流量无显著性差异(P>0.05)。通过瘘管连续收集16 h回肠末端食糜的各养分流量占全天流经回肠末端食糜相应养分总流量的比例都在68%以上,且不同采样日间无显著性差异(P>0.05)。3)通过回肠末端瘘管收集日内16 h食糜的三氧化二铬总流量及回收率在日间无显著性差异(P>0.05),平均回收率为72.9%,变异系数为6.87%。上述结果表明,在3 d的收集中,后面2 d回肠末端食糜养分的平均流量相对稳定。这2 d采食后8 h连续收集食糜有较好的代表性。建议3 d采样中,第1天作为采样预试期,后面2 d作为采样正试期。     

鸡胚盲肠上皮细胞原代培养与鉴定

为研究鸡E.tenella的宿主细胞--盲肠上皮细胞体外培养技术,为E.tenella损伤机制及抗球虫药的研究提供体外模型,分别用胰蛋白酶法、胶原酶Ⅰ法、嗜热菌蛋白酶法、嗜热菌蛋白酶+胶原酶Ⅰ法和中性蛋白酶Ⅰ+胶原酶Ⅺ法分离纯化原代鸡胚盲肠上皮细胞,通过测定细胞活力、细胞团块比例、总细胞产量和细胞团块产量,筛选出鸡胚盲肠上皮细胞最佳分离方法,并进行了纯化和培养,对培养细胞进行了鉴定.结果表明:嗜热菌蛋白酶消化、低速离心去除单细胞、差速贴壁除去成纤维细胞,为最佳分离和纯化盲肠上皮细胞的方法;分离纯化的细胞接种后分别于第3-5天、第10-11天进入对数生长期,可存活14 d以上;经形态学观察、碱性磷酸酶染色、扫描电镜鉴定为盲肠上皮细胞,所分离的细胞培养至第4、7、11天时上皮细胞比例分别为81.67%、84.33%和72.00%.用该法可获得纯度较高的原代鸡胚盲肠上皮细胞.     

Comparison of bacterial pellets and microbial markers for the estimation of the microbial nitrogen and amino acids flows from single flow continuous culture fermenters fed diets containing two-stage olive cake

The effects of using effluent bacteria (EB) and solid- (SAB) and liquid- (LAB) associated bacteria and diaminopimelic acid (DAPA) or purine bases (PB) and partially substituting alfalfa hay (AH) by a concentrate including olive cake on the microbial N flow (MNF) and amino acids (AA) flow were investigated with continuous culture fermenters fed AH and a mixture of AH and a concentrate containing barley grains and two-stage olive cake (2:1 ratio) without (AHCO) or with polyethylene glycol (PEG) (AHCOP). The MNF was not different among diets with SAB or LAB (p = 0.302 and 0.203, respectively) and DAPA, but differed with PB (p = 0.021 and 0.014, respectively). With EB both markers detected similar differences, AHCOP showing a higher value (p < 0.05) than AH and AHCO. The MNF was higher (p < 0.001) with PB than DAPA. Daily flow of non-essential AA was not different (p = 0.356) among diets but essential AA flow was higher (p < 0.05) for AH and AHCOP than for AHCO. The SAB presented lower (p < 0.05) total AA than LAB and higher total AA (p < 0.05) for diet AH than AHCO. The AA profile of EB was similar to that of LAB, but alanine and leucine were higher (p < 0.05) in EB than in LAB. Microbial contribution to AA flow was 45.4%, 55.6% and 58.1% for diets AH, AHCO and AHCOP respectively. With both markers, microbial AA flow was higher (p < 0.05) for diet AHCOP compared with AH (451 and 355 mg/day, respectively), but not different (p > 0.05) for AHCOP and AHCO (389 mg/day). The results would indicate that olive cake could be used in the practical feeding of small ruminants without negatively affecting microbial AA N supply.     

Oral administration of Lactobacillus plantarum Lq80 and Megasphaera elsdenii iNP‐001 induces efficient recovery from mucosal atrophy in the small and the large intestines of weaning piglets

Weaning causes atrophy of intestinal mucosa and a drop of IgA protection in piglets which increases vulnerability to pathogenic infections. Probiotic lactobacilli may support recovery from such weaning stresses. Butyrate‐produce bacteria may support the growth of colonic mucosa. Megasphaera elsdenii, a lactate‐utilizing butyrate producer, may help butyrate production particularly when combined with lactobacilli. Weaned piglets (Experiment 1: 20 days old, Experiment 2: 28 days old) were orally dosed once a day with either (L) 10¹⁰ (cell/dose) L. plantarum Lq80, or (LM) 10¹⁰ (cell/dose) Lq80 with 10⁹ (cell/dose) M. elsdenii iNP‐001. Lq80 was contained in capsules resistant to gastric digestion. M. elsdenii was contained in capsules resistant to gastric and intestinal digestion. An untreated control (C) was also prepared. After 2 weeks of administration, L. plantarum enhanced the recovery from the villous atrophy in both experiments. The rectal and colonic IgA tended to be higher in L and LM than in C in Experiment 1. Colonic butyrate was higher in LM than in the others in Experiment 1. The thickness of the colonic mucosa was greater in LM than in the others in Experiment 1. In early weaned piglets, the effects of L. plantarum and M. elsdenii were clear.     

Flow‐cytometric detection of phenotypic aberrancies in canine small clear cell lymphoma

Histopathology and immunohistochemistry are mandatory to solve the differential between canine low‐grade lymphoma and reactive hyperplasia. However, clinicians and owners often show reluctance toward these invasive tests. However, molecular biology techniques are still not sensitive and specific enough to be regarded as a reliable tool for final diagnosis. In humans, flow cytometry (FC) allows a definitive diagnosis of T‐cell lymphoma based on high prevalence of antigen aberrancies. We describe here the immunophenotype of 26 cases of suspect canine small‐clear cell lymphoma, determined by multi‐colour FC. All cases showed antigen aberrancies and therefore neoplasia was always confirmed. As a consequence, we argue that the combined use of cytology and FC allows solving the differential diagnosis between small clear cell lymphoma and non‐neoplastic reactive conditions when histopathology is not available. Further studies are needed to establish if any aberrancy can be considered indicative of specific histotypes.     

复合异位酸对山羊小肠氨基酸流通量和表观消化率的影响

试验研究了日粮添加复合异位酸对山羊小肠氨基酸流通量和表观消化率的影响。采用3×3拉丁方试验设计,选用3头安装有永久性瘤胃瘘管、十二指肠近端瘘管和回肠远端瘘管、平均体重为(25.4±0.75)kg的健康麻城黑山羊为试验动物。I组为空白对照,饲喂基础日粮。II组、III组分别饲喂含0.3%和0.6%复合异位酸(钠盐形式)的试验日粮。采用Co-EDTA标记法测定小肠氨基酸流通量和表观消化率。结果显示:III组缬氨酸和异亮氨酸十二指肠流通量极显著高于对照组(P0.01),亮氨酸和必需氨基酸显著高于对照组(P0.05);缬氨酸和丙氨酸的小肠表观消化率显著高于对照组(P0.05)。II组缬氨酸和异亮氨酸十二指肠流通量显著高于对照组(P0.05)。III组异亮氨酸十二指肠流通量显著高于II组(P0.05)。     

不同酸度的乳酸菌饲料添加剂对6月龄梅花鹿消化率及小肠微生物氮流量的影响

试验通过研究不同酸度的乳酸菌添加剂对6月龄梅花鹿的采食量、氮平衡、消化率以及小肠微生物氮流量的影响,确定乳酸菌添加剂在梅花鹿饲喂中的适宜酸度。结果表明:添加不同酸度的乳酸菌可明显提高梅花鹿对DM、OM、CF、CP以及氮采食量(P<0.05),其中以未调酸的乳酸菌组各种营养成分采食量最高;DM、OM、CF采食量,各组间差异显著(P<0.05),氮的采食量,除调酸组与未调酸组间差异不显著外(P>0.05),其余各组间差异显著(P<0.05)。不同酸度的乳酸菌饲料添加剂可提高梅花鹿DOM、DCF、氮沉积以及小肠微生物氮流量,未调酸组的DOM、DCF、氮沉积以及小肠微生物氮流量显著高于对照组(P<0.05)。