Influences of different dietary contents of macrominerals on the availability of trace elements in horses

In this study, influences of a reduced macromineral intake on the trace element metabolism in horses at maintenance were investigated. Background of this study is the revised recommendation on the macromineral supply for horses (GfE 2014 ). Balance studies on three adult pony geldings with body weights of 405 / 348 / 384 kg were performed to obtain data on apparent digestibility (aD), retention and serum concentrations of different trace elements (Cu, Zn, Se) at different dietary macromineral levels. A mineral supplement or a complementary feed—with a reduced macromineral content—was added to a hay‐based diet (daily 5.5 kg hay per animal, split in three servings a day), beside distilled water was offered. The diets were offered one after the other in a way that all ponies had the same sequence of treatments. The native macromineral contents of the daily offered amount of hay already surpassed the new recommendations whereas dietary trace elements needed to be supplemented. There were no statistically significant differences (p ≤ .05) concerning the aD of copper, zinc and selenium comparing the diets with and without macromineral supplementation. Serum levels of these three trace elements were not affected by the different macromineral content of the diet. Results of this study, based on a 22‐day feeding period for each treatment, indicate that a macromineral supplementation of a hay‐based diet for adult horses at maintenance was not necessary. However, no negative effects of added macrominerals on the trace element metabolism occurred in this study.     

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.     

Mineral absorption in tapirs (Tapirus spp.) as compared to the domestic horse

To test whether mineral recommendations for horses are likely to guarantee adequate mineral provision for tapirs (Tapirus spp.), we investigated the apparent absorption (aA) of macro and micro‐minerals in 18 tapirs from five zoological institutions in a total of 24 feeding trials with total faecal collection. Samples of feeds and faeces were analysed for Ca, P, Mg, Na, K, Fe, Cu and Zn. The resulting aA coefficients and the linear relationships of apparently absorbable dietary mineral content to total dietary mineral content (per 100 g dry matter) were compared with data for domestic horses. While there were no apparent differences in the absorption patterns for P, K, Na, Fe, Cu or Zn, the absorption of both Ca and Mg was distinctively higher in tapirs than in horses. Tapirs are browsers that are adapted to a diet of higher Ca content and higher Ca:P ratio than equids, and high absorptive efficiency for Ca might have evolved to ensure that high dietary Ca concentrations do not lead to the binding of dietary P in the intestine, making it unavailable for hindgut microbes. Similar to other hindgut fermenters, in tapirs, absorption coefficients for Ca increased with dietary Ca:P ratio, and urinary Ca:creatinine ratios increased with dietary Ca. Several zoo diets used were deficient in one or more minerals. When compared with faeces of free‐ranging animals, faeces of zoo animals had higher concentrations of most minerals, probably indicating a lesser diluting effect of indigestible fibre in zoo animals.     

Mineral absorption in the black rhinoceros (Diceros bicornis) as compared with the domestic horse

To test whether mineral recommendations for horses are likely to guarantee adequate mineral provision for black rhinoceroses (Diceros bicornis), we investigated the apparent absorption (aA) of macro- and microminerals in eight black rhinoceroses from three zoological institutions in a total of 32 feeding trials with total faecal collection, with additional data from three unpublished studies (18 feeding trials). Feeds and faeces were analysed for Ca, P, Mg, Na, K, Fe, Mn, Cu, Zn and Co. The resulting aA coefficients, and the linear relationships of apparently absorbable dietary mineral content to total dietary mineral content [per 100 g dry matter (DM)], were compared with data for domestic horses. Rhinoceroses had significantly higher aA coefficients for Ca and Mg (because of a higher calculated 'true' absorption), and lower ones for Na and K (because of calculated higher endogenous faecal losses). High absorption efficiency for divalent cations is hypothesized to be an adaptation to a natural diet of particularly high Ca:P ratio (approximately 14:1); an effective removal of Ca from the ingesta guarantees sufficient P availability at the fermentation site in the hindgut. Higher faecal losses of Na and K are hypothesized to be linked to a higher faecal bulk per DM intake in black rhinoceroses as compared with horses because of a generally lower digestive efficiency. There were no relevant differences in the absorption patterns of microminerals. In particular, there were no discernable differences in Fe absorption within the rhinoceroses for diets with and without tannin supplementation. Several of the zoo diets assessed in this study were deficient in Cu, Mn or Zn, and most contained excessive levels of Fe when compared with horse requirements. The findings of this study indicate that differences in mineral absorption between occur even between species of similar digestive anatomy; that in particular, Ca absorption might vary between hindgut fermenters with Ca:P ratio in their natural diet; that Na might be a particularly limiting factor in the ecology of free-ranging rhinoceroses; that moderate doses of tannins do not seem to markedly influence mineral absorption; and that diets for captive animals should contain adequate, but not excessive mineral levels.     

Changes of serum macromineral concentrations relative to the body weight gain of growing yaks throughout a year-round

Concentrations of blood serum macromineral calcium, phosphorus, sodium, chlorine and potassium of 6 to 40 months old growing yaks were determined bi-monthly with Beckman Synchron CX System, and body weights were also recorded in a production year-round. The body weight of growing yaks showed a pattern of rapidly gaining more weight in warm seasons and gradually losing about one fifth of it in cold seasons except of the uncompleted weaned younger animals. In the harsh cold seasons, the serum P dropped to an abnormally low level, while the serum Ca was maintained in a relatively constant level, which implied that much more restored Ca may be released to blood stream from the animal's skeleton to maintain the Ca in homeostasis during the prolonged deficiency of forage intake. Both of the serum levels of Ca and P peaked in September, correspondently, the greatest body weight gain occurred in the same month. Except serum level of K, all the serum levels of macrominerals studied have positive correlations with the living body weight of growing yaks(P < 0.05). Providing supplements with macrominerals, especially P and Ca in cold seasons, are necessary for the growth of yaks and will be benefit local farmers in the improvement of the yak production performance.     

Tooth length and incisal wear and growth in guinea pigs (Cavia porcellus) fed diets of different abrasiveness

Dental diseases are among the most important reasons for presenting guinea pigs (Cavia porcellus) and other rodents to veterinary clinics, but the aetiopathology of this disease complex is unclear. Clinicians tend to believe that the ever‐growing teeth of rabbits and rodents have a constant growth that needs to be worn down by the mastication of an appropriate diet. In this study, we tested the effect of four different pelleted diets of increasing abrasiveness [due to both internal (phytoliths) and external abrasives (sand)] or whole grass hay fed for 2 weeks each in random order to 16 guinea pigs on incisor growth and wear, and tooth length of incisors and cheek teeth. There was a positive correlation between wear and growth of incisors. Tooth lengths depended both on internal and external abrasives, but only upper incisors were additionally affected by the feeding of whole hay. Diet effects were most prominent in anterior cheek teeth, in particular M1 and m1. Cheek tooth angle did not become shallower with decreasing diet abrasiveness, suggesting that a lack of dietary abrasiveness does not cause the typical ‘bridge formation’ of anterior cheek teeth frequently observed in guinea pigs. The findings suggest that other factors than diet abrasiveness, such as mineral imbalances and in particular hereditary malocclusion, are more likely causes for dental problems observed in this species.     

Neutralizing antibody to bovine rotavirus in various animal species

A total of 288 serum samples were collected from 12 species of animals in various localities of Japan from 1975 to 1977. Neutralizing antibody to bovine rotavirus was found in serum samples from all the species, viz., horses, cattle, sheep, goats, pigs, dogs, rabbits, guinea pigs, rats, mice, chickens and human beings. The incidence of neutralizing antibody in titers of 1 : 2 or higher ranged from 31 to 100%, and high incidences exceeding 70% were obtained in horses, cattle, sheep, pigs, dogs, rabbits and human beings. High titers were most common in horses, cattle, sheep and pigs. These serological results suggest that rotaviruses occur commonly in these species of animals.     

不同驱虫药对伊犁马营养物质表观消化率的影响

[目的] 研究不同驱虫药对伊犁马营养物质表观消化率的影响,为驱虫药在马属动物养殖中的科学应用提供参考。[方法] 选择平均体重相近的1岁龄伊犁马40匹,随机分为5组,每组8匹（公母各半）,分别为对照组、试验Ⅰ组、试验Ⅱ组、试验Ⅲ组和试验Ⅳ组。在相同的饲养管理和日粮营养水平条件下,对照组马不驱虫,试验Ⅰ组马灌服伊维菌素乳剂0.1 mL/（kg·BW）,试验Ⅱ组马灌服吡喹酮片剂0.01 g/（kg·BW）,试验Ⅲ组马灌服阿苯达唑片剂0.025 g/（kg·BW）,试验Ⅳ组马灌服伊维菌素10 mg/（kg·BW）+阿苯达唑350 mg/（kg·BW）。驱虫后进行20 d的消化代谢试验,预试期15 d,正试期5 d;正试期采用全收粪法采集样品,测定或计算马营养物质消化代谢指标。[结果] 试验Ⅳ组的干物质（DM）、有机物（OM）、粗蛋白（CP）、总能（GE）、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）、磷（P）采食量和排出量高于其他4组（P>0.05）。试验Ⅱ组和试验Ⅲ组的DM、OM、GE、NDF、ADF、Ca和P消化量与对照组相比均有所提升（P>0.05）。与对照组相比,试验Ⅱ组的DM、OM、CP、GE、NDF、ADF、Ca和P表观消化率提高幅度分别为1.91%、1.87%、1.42%、2.27%、3.05%、2.13%、13.68%和2.06%（P>0.05）,试验Ⅲ组的DM、OM、GE、NDF、ADF、Ca和P表观消化率与对照组相比提高幅度分别为2.45%、2.83%、2.26%、2.10%、1.20%、20.24%和6.55%（P>0.05）;试验Ⅳ组除Ca的表观消化率高于对照组（P>0.05）,其余营养物质的表观消化率均低于对照组（P>0.05）。[结论] 在该试验条件下,单独使用吡喹酮片剂或阿苯达唑片剂对1岁龄伊犁马进行驱虫处理,对提高营养物质表观消化率表现出一定的积极作用。     

Effect of dietary inclusion of benzoic acid on mineral balance in growing pigs

The objective of this study was to determine the effect of dietary inclusion of benzoic acid on utilization of the macrominerals Ca, P, Mg, K, Na, and Cl in growing pigs. Eighteen barrows, initial BW of 28 ± 1.7 kg, were assigned to 3 diets: a basal diet based on barley, wheat, soybean meal, corn, and field pea and formulated to contain 9.31 MJ NE kg^− 1 and 8.84 g^− 1 kg standardized ileal digestible lysine, or the basal diet containing 10 or 20 g kg^− 1 benzoic acid by replacing tapioca starch. The pigs were fed the experimental diets a rate of 2.7 times the maintenance requirement for ME for 21 days. Faeces and urine were collected quantitatively from days 11 to 21, and blood and plasma was collected on days 1, 10, and 21. On day 21, the pigs were killed and the left femur was removed. Benzoic acid linearly decreased (P = 0.001) the urine pH from 7.32 to 5.32, and quadratically increased (P < 0.05) blood pH on day 21. Benzoic acid linearly increased (P < 0.05) the apparent total tract digestibility (ATTD) of Ca, P, and Na from 65 to 72%, 46 to 55%, and 78 to 90%, respectively, linearly decreased (P < 0.05) the ATTD of Cl from 94 to 93%, and did not affect the ATTD of Mg and K. Benzoic acid linearly increased (P < 0.05) the retention of Ca, P, and K from 58 to 67%, 46 to 54%, and 31 to 38%, respectively, linearly decreased (P < 0.05) the retention of Na and Cl from 57 to 48% and 75 to 44%, respectively, and did not affect retention of Mg. On day 21, benzoic acid linearly increased (P = 0.001) plasma P and quadratically increased (P < 0.05) plasma K or tended to increase (P = 0.05) plasma Na. Benzoic acid linearly reduced (P < 0.05) the concentration of ash in femur but not the amount of ash, reduced (P < 0.05) the concentration of Ca and Cl in femur ash, and linearly increased (P < 0.05) the concentration of P in femur ash. In summary, benzoic acid increased the utilization of dietary Ca, P, and K, did not affect the utilization of dietary Mg, and reduced the utilization of dietary Na and Cl. During swine feed formulation, effects of benzoic acid on macromineral utilization should be considered to ensure that macromineral requirements are met and not exceeded following benzoic acid supplementation.     

Comparison of Hydrolytic and Conjugative Biotransformation Pathways in Horse, Cattle, Pig, Broiler Chick, Rabbit and Rat Liver Subcellullar Fractions

To complete a studyaimed at investigating the pattern of the basal activities of liver xenobioticmetabolizing enzymes in major and minor species intended for meat production, microsomal carboxylesterases and some conjugating enzyme activities were determined and compared in liver preparations from horses, cattle, pigs, rabbits and broiler chicks, using the rat as a reference species. Horses and broiler chicks exhibited a lower microsomal carboxylesterase activity towards indophenyl or p-nitrophenyl acetate than that measured in cattle or pig subfractions. Among food-producing species, the rate of glucuronidation of either 1-naphthol or p-nitrophenol was in the order pigs ∼rabbits > horses >> cattle > broiler chicks. The widest variations were observed in the acetylation capacity towards p-aminobenzoic acid or isoniazid, which in rabbits was 3-fold to 11-fold greater than that displayed by any other examined species; low but measurable activities were found in equine and bovine cytosols. The activity of cytosolic glutathione S-transferase (GST) accepting the general substrate 1-chloro-2,4-dinitrobenzene was significantly higher in rabbits, horses and pigs than in rat, broiler chicks and cattle. Finally, an uneven pattern of activity towards the other tested GST substrates – 3,4-dichloronitrobenzene, ethacrinic acid or 1,2-epoxybutane – was observed, possibly reflecting the species-related expression of different GST classes; in this respect, the conjugative capacity displayed by horses was higher than or comparable to that found in the other food-producing species.     

Detection of all Chlamydophila and Chlamydia spp. of veterinary interest using species-specific real-time PCR assays

The aim of the present study was to analyse the occurrence of chlamydiae in several mammalian host species. Clinical samples that previously tested positive in a Chlamydiaceae-specific real-time PCR were retested using six species-specific real-time PCR assays to identify the chlamydial species involved. Chlamydophila (Cp.) abortus was the agent most frequently found in cattle, sheep, horses, goats, and pigs. Detection in cattle of Cp. psittaci (11% of samples) and Chlamydia (C.) suis (9%), as well as Cp. psittaci in a goat sample was somewhat unexpected. DNA of two different chlamydiae was identified in 56 (12.7%) of 440 samples tested. Cp. felis was the predominant species found in cats, while in guinea pigs and rabbits only Cp. caviae was detected. Interestingly, the latter two pathogens were also identified in samples from dogs. The data show that mixed chlamydial infections are not rare and suggest an extended host range of individual species.     

Effect of physical training on nutrient digestibility and faecal fermentative parameters in Standardbred horses

This study aimed at evaluating, in previously inactive Standardbreds horses, the effect of 5 weeks of an exercise training programme on nutrient digestibility and faecal fermentative parameters (FFPs). As an increase in digestibility had previously been reported in trained endurance horses, we hypothesized that similar results would be found in horses being trained for other types of exercise on a different type of diet. After 3 weeks of dietary adaptation, a digestibility trial (DT1) was undertaken, over 3 days, in eight untrained Standardbreds with a fresh faecal sample being collected on the second day for FFP determinations. Six of the eight horses undertook a training programme, and after 5 weeks of exercise, the DT and the FFP measurements were then repeated (DT2). DT2 began after 3 days of inactivity. The same natural meadow hay (H) and pelleted complementary feed (CF) were fed throughout. For 5 days before the DTs, horses were fed 2.1% BW on a dry matter basis (55:45 ratio H:CF). Body weight and body condition score remained constant. Apparent digestibility of dry matter, organic matter, neutral detergent fibre, hemicellulose, crude protein and gross energy, as well as faecal total volatile fatty acids (VFA), acetate and propionate concentrations were significantly (p < 0.05) higher at DT2 than at DT1. A 5‐week exercise programme had a positive impact on nutrient digestibility and FFP. Training may improve dietary energy supply, in particular via increased hindgut VFA production. The potential improvement of digestive efficiency with training should be taken into account when formulating nutritional recommendations for the exercising horse, particularly when performing light work, which is low‐intensity exercise for 1–3 h per week.     

Effect of cation–anion balance in feed on urine pH in rabbits in comparison with other species

In the present investigation, the impact of diet composition on urine pH in rabbits was compared with previous studies on rabbits, cats, dogs, pigs and horses. A total of 13 dwarf rabbits were fed six different diets with a cation–anion balance (CAB) between ?39 and +320 mmol/kg dry matter (DM) using ammonium chloride (NH₄Cl) as an acidifier. CAB was calculated as follows: CAB (mmol/kg DM) = 49.9*Ca + 82.3*Mg +43.5*Na + 25.6*K ? 59*P ? 62.4*S ? 28.2*Cl; minerals in g/kg DM. Urine, faeces and blood were collected. Urine pH ranged from 5.26 ± 0.22 at a CAB of ?39 mmol/kg DM to 8.56 ± 0.24 at a CAB of +320 mmol/kg DM. A low CAB in the feed reduced blood pH and blood base excess significantly. Renal excretion of Ca, P, Na and Mg and water was significantly higher in rabbits eating acidifying diets. In comparison with other species, rabbits reacted to acidifying diets in a similar way as cats, dogs and pigs. Rabbits on a mildly alkalizing diet, however, had a trend to higher urine pH than other monogastric species on such diets (cats, dogs, pigs, horses).     

Effects of dietary supplementation of an enzyme blend on the ileal and fecal digestibility of nutrients in growing pigs

The objective of this experiment was to determine the effect of a beta-glucanase-protease enzyme blend product (EBP) on fecal digestibility (FD), apparent ileal digestibility (AID), standardized ileal digestibility, and digestibility in the hindgut of growing pigs. Twelve ileal-cannulated, growing barrows (38.2 +/- 0.5 kg) were housed in individual metabolism crates, blocked by previous feed intake into 3 groups with 4 pigs each, and randomly assigned to 1 of 4 treatments within a square (group) of 3 replications of 4 x 4 Latin square design. Treatments were basal diet (Basal), Basal + 0.05% of EBP (0.05% EBP), Basal + 0.10% of EBP (0.10% EBP), and hydrolyzed casein for measurement of endogenous amino acids. The Basal diet consisted of corn and soybean meal and was calculated to have 3.36 Mcal of ME/kg and 1.1% of total lysine, as-fed basis. Feed intake of each replicate of the Latin square during the first period was 85% of the minimum feed intake of the 4 pigs during the preliminary period and was equalized within each square. The feeding level was increased by 100 g/d in each subsequent period. Each of the experimental periods was 14 d, including 4 d of dietary adaptation, 5 d of fecal collection, 3 d of transition period, and 2 d of ileal collection. Ileal effluents were collected continuously for the same 12-h interval each day. Pigs fed the EBP demonstrated increased (P < 0.05) FD of DM, OM, energy, CP, nonfiber carbohydrate, total dietary fiber, insoluble dietary fiber, acid-hydrolyzed fat, ash, Ca, and P compared with pigs fed Basal. The AID of NDF and hemicellulose was increased (P < 0.05) by supplying the EBP either at 0.05 or 0.10% in the diets, but AID of DM and energy was not increased. The AID of acid-hydrolyzed fat tended to be greater (P = 0.051) for the pigs fed the EBP than for those fed Basal. Ileal digestibility of most amino acids was not affected by treatment, but the EBP reduced the apparent and standardized digestibility of methionine, alanine, and serine (P < 0.05). The difference between FD and AID of hemicellulose was lower (P < 0.05) for the pigs fed the EBP than for those fed Basal. These results demonstrated that the EBP fed to growing pigs improved the FD of DM, OM, energy, CP, nonfiber carbohydrate, total dietary fiber, acid-hydrolyzed fat, Ca, and P, and the AID of NDF and hemi-cellulose, but the standardized ileal digestibility of amino acids was not improved by supplying the EBP in corn-soybean meal-based diets of growing pigs.     

Surgical sterilization in small mammals. Spay and castration.

The intrinsic physiologic and anatomic differences between small exotic mammals and the species that are more familiar to veterinary practitioners (i.e., dogs and cats) are substantial. This discussion is limited to rabbits, mice and rats (murid rodents), hamsters and gerbils (cricetid rodents), and guinea pigs and chinchillas (hystricomorph rodents). In addition to their anatomic and physiologic differences, differences in behaviors, such as their reaction to stress and pain, exist. Preoperative and postoperative care, basic surgical techniques unique to these species, and useful materials are discussed.     

Gastrointestinal Disease in Exotic Small Mammals

Exotic small mammal medicine is a relatively new specialty area within veterinary medicine. Ferrets, rabbits, and rodents have long been used as animal models in human medical research investigations, resulting in a body of basic anatomic and physiologic information that can be used by veterinarians treating these species. Unfortunately, there is a paucity of veterinary articles that describe clinical presentation, diagnosis, and treatment options of gastrointestinal (GI) disease as it affects exotic small mammals. Although there is little reference material relating to exotic small mammal GI disease, patients are commonly presented to veterinary hospitals with digestive tract disorders. This article provides the latest information available for GI disease in ferrets (Helicobacter mustelae gastritis, inflammatory bowel disease [IBD], GI lymphoma, systemic coronavirus, coccidiosis, and liver disease), rabbits (GI motility disorders, liver lobe torsion, astrovirus, and coccidiosis), guinea pigs (gastric dilatation volvulus [GDV]), rats (Taenia taeniaeformis), and hamsters (Clostridium difficile). Both noninfectious diseases and emerging infectious diseases are reviewed as well as the most up-to-date diagnostics and treatment options.     

饲粮纤维源及粗纤维水平对肉兔营养物质消化率、肠道消化酶活性及盲肠菌群多样性的影响

本试验旨在研究饲粮纤维源及粗纤维(CF)水平对肉兔营养物质消化率、肠道消化酶活性及盲肠菌群多样性的影响。试验采用双因子试验设计,依据等能等氮原则,设2种纤维源(苜蓿草粉、稻壳粉)、3个CF水平(12%、14%、16%),共配制6种试验饲粮。选择144只70~80日龄、平均体重(2 002±77)g的健康伊拉生长肉兔,随机分为6组,每组4个重复,每个重复6只兔,单笼饲养。饲养试验为期4周,饲养试验期末,采用全收粪法进行消化试验,之后进行屠宰,取肠道食糜用于消化酶活性及盲肠菌群多样性的测定。结果表明:1)苜蓿草粉组干物质(DM)、CF、酸性洗涤纤维(ADF)、木质素(ADL)的消化率显著或极显著高于稻壳粉组(P0.05或P0.01),粗蛋白质(CP)消化率则极显著低于稻壳粉组(P0.01);12%CF水平组DM、中性洗涤纤维(NDF)、ADF的消化率显著高于14%CF水平组(P0.05),同时该组能量的消化率及表观消化能(ADE)极显著高于14%、16%CF水平组(P0.01)。2)稻壳粉组十二指肠胰蛋白酶活性极显著高于苜蓿草粉组(P0.01)。与14%、16%CF水平组相比,12%CF水平组的空肠淀粉酶、胰蛋白酶活性及盲肠纤维素酶活性均最低。3)纤维源对盲肠菌群丰富度和香农指数无显著影响(P0.05),但苜蓿草粉组的盲肠菌群均衡指数极显著高于稻壳粉组(P0.01)。CF水平对盲肠菌群丰富度和香农指数有显著影响(P0.05),其中16%CF水平组的数值均为最高。综上所述,在本试验条件下:1)苜蓿草粉组肉兔DM、CF、ADF、ADL的消化率及盲肠菌群均衡指数显著或极显著高于稻壳粉组,但十二指肠胰蛋白酶活性极显著低于稻壳粉组。2)饲粮CF水平为12%时肉兔的ADE和各主要营养物质的消化率最高;CF水平越高,肉兔空肠淀粉酶、胰蛋白酶活性和盲肠纤维素酶活性越高;饲粮CF水平为16%时肉兔盲肠菌群的多样性较高。     

Studies on dioctyl sodium sulfosuccinate toxicity: clinical, gross and microscopic pathology in the horse and guinea pig.

Concentrations of dioctyl sodium sulfosuccinate (DSS) ranging from three to five times the recommended dosage produced severe diarrhea, rapid dehydration and death in seven horses and 66 guinea pigs when administered experimentally per os. Clinicopathological findings indicated hemoconcentration in both horses and guinea pigs. There was a leucocytosis in the guinea pigs given the highest dosages. In all cases the principal finding at necropsy was extreme fluid distention of the intestinal tract. There was histopathological evidence of epithelial denudation and vascular stasis. The LD50 in the guinea pig was approximately 0.65 g DSS/kg body weight.     

Factors associated with improved haemagglutination by African horse sickness virus

Concentrated cell culture fluids of African horse sickness virus were shown to agglutinate erythrocytes from cattle, horses, sheep, goats, guinea pigs, rabbits, and poultry at 4°C, room temperature, and 37°C. The titres obtained were dependent on pH and NaCl molarity of the diluent, optimal titres being obtained at pH 7.5 and 0.6 M NaCl. The HA inhibiting antibodies to two AHS viruses were proven to be type specific.