Dietary effects on bifidobacteria and Clostridium perfringens in the canine intestinal tract

Dietary effects on the intestinal microflora have gained increasing interest because of the evidence that a balanced micro ecology in the gut is important for health and well being. The aim of the present study was to evaluate the effect of different diets on faecal counts of bifidobacteria and Clostridium perfringens in dogs. Two extruded, dry diets, one supplemented with 3% chicory (1.5% inulin), a non-digestible oligosaccharide (NDO) and the other with 3% glucose (GLU) were compared with a protein rich diet (PR+) based on low quality animal derived protein sources (NDO 265, GLU 259, PR+ 726 g crude protein/kg dry matter; greaves meal and bovine lung as protein sources in PR+). Nine adult beagles were subjected to a consecutive cross-over trial. All dogs started with diet PR+, after which groups of four dogs (group A) received GLU and the other five dogs (group B) received NDO. After an intermediate wash-out period with diet PR+ for 3 weeks the A dogs were switched to diet NDO and B dogs to GLU. In the final period all dogs were fed with diet PR+. Faecal samples were collected during each period for dry matter and pH measurements. Faecal bifidobacteria and Cl. perfringens were quantified in fresh samples at the end of each feeding period and additionally on the first days after feed change from the dry diets to diet PR+. Diets NDO and GLU increased faecal dry matter and reduced faecal pH from 6.9 to 7.4 with the high protein diet to 5.9-6.5. The dry diets induced a firmer faecal consistency and a lower faecal pH, with no significant difference between NDO or GLU. Clostridium perfringens was found in all faecal specimens after feeding PR+ with counts of log 8.2-8.8 colony forming units (cfu)/g faeces. Both dry diets reduced the counts of Cl. perfringens significantly (log 3.3-4.0 cfu/g faeces). Switching from the dry diets to the high protein diet induced an increase of Cl. perfringens within 1 day, independent of the previous diet. In dogs fed PR+, bifidobacteria were detected in only four faecal samples and exclusively in the initial feeding period. During the remainder of the experiment the counts fell below the detection limit (log 6 cfu/g faeces). The faecal concentrations of bifidobacteria increased with both dry diets. Slightly higher concentrations (log 9.6-9.7 cfu/g faeces) were obtained from dogs fed the dry diet containing NDO compared with the diet containing glucose (log 9.3-9.4 cfu/g faeces). The increase was small which may be related to the level of total fermentable carbohydrates in both diets which alone increase remarkably the total counts of bifidobacteria. In conclusion, distinct dietary effects on the faecal counts of Cl. perfringens and bifidobacteria with a clear antagonistic pattern were observed. The main factor was the protein source and level in the diet. In this case, NDO favoured the concentrations of bifidobacteria to a limited degree. Further studies are needed to evaluate time effects, metabolic consequences and the potential implication for health promotion in pets.     

A survey of abomasal ulceration in veal calves

Abomasal ulceration was found in 264 of 304 commercially reared veal calves at slaughter. The incidence and severity of lesions were greatest in loose housed calves with access to straw and fed milk substitute ad libitum. The majority of lesions were located in the distal pylorus. There was no evidence that the abomasal erosions and ulcers found in the majority of veal calves affected their growth rate or were deleterious to their welfare. It is suggested that pyloric ulceration may be related to the diet of veal calves.     

The microflora and concentrations of volatile fatty acids in the rumen of cattle fed on single component rations

The composition of the rumen microflora and the volatile fatty acids were examined in cattle free-grazing on grass or stall-fed on hay, grass pellets, oats or dried beet pulp with molasses. Total and viable counts of anaerobic bacteria were highest on the grass feeding, but viable counts as a percentage of total counts were highest when oats or beet pulp with molasses were fed. Counts of cellulolytic bacteria were lowest on these latter 2 diets, and highest on grass or grass pellet diets. Studies of the anaerobic flora showed that the composition in animals fed on grass pellets resembled more that found in animals free-grazing on grass than in those fed on hay. Counts of aerotolerant bacteria were only a small percentage of the total count, but were highest on the hay diet. On this latter diet and on grass-feeding the streptococci (identified as Streptococcus bovis) were predominant, but contrary to expectation, streptococci were found only in small numbers on the oats diet, where coryneform rods were the major type present. Although a period of 4–6 weeks was allowed for the animals to adapt to the feeds, the 2 periods of feeding on oats and dried beet pulp with molasses markedly affected the composition of the rumen flora in the subsequent periods of feeding grass pellets and hay. Ruinen volatile fatty acid analysis showed a propionogenic effect of oats and the highest percentage of butyric acid when beet pulp with molasses was fed. The expected propionogenic effect of grass pellets was not observed.     

Dynamics of protozoan counts in the rumen of calves during a period of milk feeding]

Protozoan counts were followed in the rumen of calves in the period of milk diet. In the third week of calves' age the total counts of protozoans in 1 ml of rumen contents made 1.48 +/- 0.91 (log 10 +/- SEM). These counts were increasing gradually to reach in the seventh week of age the value of 5.54 +/- 0.19 (log 10 +/- SEM) in 1 ml of rumen contents. An increase in the protozoan counts in the seventh week of age was significant in comparison with the preceding four weeks. Total protozoan counts were converted also per 1 g of rumen content dry matter.     

Haematology of veal calves reared in different husbandry systems and the assessment of iron deficiency

Calves were reared for veal and fed milk replacer either alone or with straw or dry feed of varied iron content. Measurements of haematology and iron biochemistry were made at the start of the rearing period and before slaughter at 16 to 20 weeks of age. When the total dietary iron intake rose to approximately 12,500 mg (an average of 112 mg/dl, approximately 60 mg/kg dry matter) haemoglobin concentration reached a mean value (+/- sd) of 12.4 +/- 1.1 g/dl, similar to control calves. There was no further increase in haemoglobin when more iron was fed, indicating that there was sufficient iron in the diet for normal erythropoiesis. The borderline of iron deficiency anaemia at 16 to 20 weeks of age was defined as a haemoglobin concentration of 9 g/dl and a saturation of total iron binding capacity of 10 per cent. There was evidence of diurnal variation in serum iron concentration in calves fed in a periodic manner. The feeding of straw to veal calves did not prevent iron deficient erythropoiesis.     

Glucose and insulin metabolism in ruminating and veal calves fed high and low fat diets.

Holstein male calves were maintained on conventional (milk to 6 wk of age, fed grain and hay after weaning) and veal (milk replacer only) diets to 16 wk of age. Within each of these 2 physiological states (ruminating or non-ruminating), calves were fed low or high fat diets (ruminating: 3 and 10%; veal: 10 and 18%). Glucose tolerance tests were undertaken at 8 and 16 wk of age in each group. Basal concentrations (4 hr postfeeding) and areas under the response curves for plasma glucose and insulin were higher in veal calves (P < .0001). Ruminating calves fed higher fat utilized glucose more readily (smaller areas under the curves for both glucose and insulin, P < .10) than those fed lower fat. Age did not influence basal glucose concentrations (P > .10), but older calves had higher basal insulin (P < .0001) and greater areas under the curves (P < .0005) for both glucose and insulin after a glucose challenge. Rate of clearance (k) was greater in ruminating calves (P < .001). Though rate of clearance in veal calves was slower, larger plasma pool size caused veal calves on average to utilize glucose at a 15% greater rate per kg body weight than ruminating calves. Whereas fat concentration in the diets did not influence glucose metabolism in veal calves, the high lactose content (> 50% of diet dry matter) of veal diets induced severe insulin resistance in these calves.     

Effects of the provision of large amounts of solid feeds to veal calves on growth and slaughter performance and intravitam and postmortem welfare indicators

Polish Friesian male calves (n = 78) were used to investigate the effects of innovative feeding plans based on the provision of large amounts of solid feeds on growth performance, welfare, and carcass characteristics of veal calves. Groups of calves (initial BW 71.5 ± 3.7 kg) were fed 1 of 3 treatments (26 calves/treatment): 1) milk replacer plus corn grain (CG), 2) milk replacer plus an 80:20 mixture (as-fed basis) of corn grain and wheat straw (CGS), or 3) milk replacer plus a 72:20:8 mixture (as-fed basis) of corn grain, wheat straw, and extruded soybean, respectively (CGSES). All the treatments provided at least 170 kg DM/calf from solid feed throughout the 206 d of fattening. Type and concentration of milk replacer were the same for all calves throughout fattening. Calves fed CGSES received 96% of the daily amount of milk replacer delivered to CG and CGS to balance the dietary CP content. No differences (P ≥ 0.063) among treatments were observed for growth performance and DMI. Health status of CG calves was less than CGSES calves, as indicated by the greatest (P < 0.001) proportion of milk replacer refusal events and the greatest (P < 0.001) incidence of treatments for respiratory disorders. Inclusion of straw and soybean in the solid feeds increased (P < 0.001) the daily intake of iron in CGS and CGSES as compared with CG; however, blood hemoglobin concentrations measured at d 5 and 31 were greater (P < 0.05) than when measured on d 80, 122, and 206 of fattening. Feeding treatment did not (P ≥ 0.107) affect HCW, dressing percentage, or carcass color. Calves fed CG had heavier (P < 0.001) reticulorumens and more (P < 0.001) developed rumens than CGS and CGSES calves, but 84% and 68% of CG rumens (P < 0.001) showed overt signs of hyperkeratinization and plaques, respectively. These alterations of rumen mucosa were not detected in CGSES calves, and only 8% of CGS calves had rumen plaques. Regardless of feeding treatment, postmortem inspection recorded a prevalence of more than 84% abomasal lesions. When feeding veal calves with large amounts of solids, it is advisable to avoid the provision of corn grain alone and replace part of the cereal with a roughage source to improve calf health and prevent rumen mucosa alterations.     

The provision of solid feeds to veal calves: I. Growth performance, forestomach development, and carcass and meat quality

Growth performance, forestomach development, and carcass and meat quality of veal calves fed a milk replacer diet (Control) were compared to those obtained from calves fed the same liquid diet plus 250 g x calf(-1) x d(-1) of dried beet pulp or wheat straw. Three groups of 46 Polish Friesian calves, balanced according to initial BW, were assigned to the three dietary treatments in a fattening trial, which lasted 160 d. The provision of either solid feed did not affect the milk replacer intake. However, calves' ADG was increased (P < 0.01) only by feeding the beet pulp diet. The administration of both solid feeds improved calves' health status; calves fed solid feeds required fewer iron treatments for low hemoglobin and needed less medical treatments for respiratory or gastrointestinal diseases. In comparison to the Control calves, the provision of wheat straw and beet pulp increased iron intake throughout the fattening period by 41 and 130%, respectively. However, only calves fed beet pulp showed higher levels of hemoglobin and plasma iron concentrations (P < 0.05), whereas the same blood parameters were similar between Control calves and those fed wheat straw. At slaughter, both solid feeds led to empty forestomach weights heavier than those of Controls without reducing dressing percentage. The reticulorumen was heaviest in calves fed beet pulp, whereas wheat straw promoted omasal development. The administration of beet pulp resulted in a better carcass conformation than did the Control diet or wheat straw, but it had a detrimental effect on carcass color, which was graded as the darkest (P < 0.001). Consistent with this result, meat color of calves fed beet pulp was darker than that of Control calves and those fed wheat straw, because of the higher hematin concentration measured at the muscle level. No differences in carcass and meat color were observed between Control calves and calves fed wheat straw. The administration of solid feeds for welfare purposes does not always prevent the production of veal meat fulfilling the color standards required by the market. There is not a straight-forward relationship between a solid feed's iron content and the "redness" of veal meat, which should be related to the capability of the calves to use the iron provided by the roughage.     

Sulfur influences on rumen microorganisms in vitro and in sheep and calves

When continuously cultured ruminal microbes were given orchardgrass hay and sufficient sulfuric acid or hydrochloric acid to maintain a pH of 5.5, fermentation and numbers of protozoa were reduced compared with cultures whose pH was controlled with phosphoric acid. Likewise, when sulfur-deficient, purified diets were supplied to cultures, less methane (mmol X liter-1 X d-1), 3.2 vs 32.6, was produced and fewer cellulolytic bacteria (log10/ml), 5.8 vs 7.2 were present than when cultures were given the same diet supplemented with .3% elemental sulfur. The rumen of sheep fed the .04% sulfur diet had reduced digesta weights (1.69 vs 3.2 kg) compared with sheep fed the diet with .34% sulfur at the same intake. There also was reduced methanogenesis 12.3 vs 25.8 mmol X liter-1 X d-1) and reduced numbers of cellulolytic bacteria (7.4 vs 8.4 log10/ml) in sulfur-deficient sheep in comparison to sulfur-supplemented sheep. In growing calves, the same types of bacteria predominated in the rumen, but more facultative anaerobic bacteria were isolated from calves fed .04% sulfur than from calves fed diets with .34 to 1.72% sulfur. None of the dietary levels of sulfur appeared toxic. Regardless of treatment, volatile fatty acids were more predominant than lactic acid as end-products of fermentation of ruminal microbes in fermenters, sheep and calves. The greater methanogenesis and the greater cellulolytic bacterial numbers of sulfur-supplemented sheep compared with sulfur-deficient in vitro cultures, is interpreted to be the result of recycling of sulfur to the rumen in sheep where it is efficiently scavengered by ruminal bacteria.     

甘露寡糖添加方式对哺乳期犊牛瘤胃细菌菌群结构的影响

为利用16S rDNA技术研究甘露寡糖不同添加方式对哺乳期犊牛瘤胃细菌菌群结构影响,本研究选用出生日龄一致、体重接近、健康状况良好的荷斯坦公犊牛20头,随机分为4组。CR组为对照组,饮用乳及开食料中均不添加甘露寡糖;ORa组在饮用乳中添加5 g甘露寡糖,开食料中不添加甘露寡糖;ORb组在开食料中添加5 g甘露寡糖,饮用乳中不添加甘露寡糖;ORc组在饮用乳及开食料中各添加2.5 g甘露寡糖(混合添加)。应用16S rDNA测序技术,研究了甘露寡糖添加方式对犊牛瘤胃细菌构建的影响。结果表明:甘露寡糖添加方式会影响哺乳期犊牛瘤胃细菌总数,但对哺乳期犊牛瘤胃细菌菌群多样性未产生显著影响(P>0.05)。在门水平上,与对照组相比,ORb组颗粒料中添加甘露寡糖显著降低了厚壁菌门与放线菌门的丰度(P<0.05),极显著提高了变形菌门的丰度(P<0.01),优势菌门增加为3种,分别为拟杆菌门、厚壁菌门与变形菌门。在属水平上,甘露寡糖不同添加方式导致哺乳期犊牛瘤胃细菌菌群结发生了改变,其中甘露寡糖不同添加方式对小杆菌属和脱硫弧菌属在瘤胃内丰度均产生了影响,但对ORa组与ORc组犊牛瘤胃细菌影响不及ORb组;且ORb组犊牛瘤胃细菌功能性菌属普雷沃氏-7属、氨基酸球菌属、优杆菌属和琥珀酸弧菌等均发生显著变化。基于以上结果,得出如下结论:本研究条件下,甘露寡糖添加方式对哺乳期犊牛瘤胃细菌菌群多样性未产生显著影响(P>0.05),但开食料中寡糖添加方式对菌群结构产生部分影响,其中发挥瘤胃蛋白降解作用和淀粉降解作用的琥珀酸弧菌科-UCG-001属、利用乳酸的新月形单胞菌属丰度极显著提高(P<0.01),而利用乳糖的优杆菌属丰度显著降低,降解半纤维素的小杆菌属丰度极显著降低(P<0.01)。     

The provision of solid feeds to veal calves: II. Behavior, physiology, and abomasal damage

The aim of this study was to evaluate the effects of the addition of two roughage sources (wheat straw and beet pulp) to the milk replacer diet of veal calves, in order to reduce stress and improve animal welfare. We allocated 138 Polish Friesian male calves to three different feeding plans: a milk replacer diet (Control), 250 g/d of wheat straw in addition to the milk replacer, or 250 g/d of dried beet pulp in addition to the milk replacer. Within each feeding treatment, 16 calves were individually housed and 30 were kept in group pens (five calves/pen). Several behavioral, physiological, and health welfare indicators were monitored throughout the fattening period, which lasted for 160 d. Abnormal oral behavior around the meals was higher in Control calves (P < 0.01), while its lowest level was observed in straw-fed calves. At the beginning of the trial, chewing was higher in calves receiving solid feeds (P < 0.001), but the difference from the Control gradually decreased and disappeared at wk 13 for calves fed beet pulp and at wk 17 for those fed wheat straw. At the end of the fattening period, no differences among treatments were found in the frequency of chewing. Regardless of the diet, self-grooming decreased with age and no relationship was observed between this behavior and the presence of rumen hairballs. Cross-sucking was performed with low frequencies (from 4.70% at wk 2 to 1.05% at wk 23 around the meals, and even lower far from the meals) and was not affected by the provision of roughage. The time in contact with the bucket during the whole day was higher in Controls, whereas calves fed wheat straw maintained a lower level of this activity until the end of the trial (P < 0.01). The calves fed wheat straw spent more time in contact with the feed trough (P < 0.001) than those fed beet pulp and Control calves. No differences were found in cortisol curves due to the feeding treatment. In calves fed beet pulp, most hematological measures statistically differed from the other treatments, possibly in response to the higher iron intake and(or) to the higher hemoconcentration, probably due to the administration of beet pulp as dried feed. The incidence of abomasal ulcers and erosions was increased by the provision of the solid feeds, particularly by a structured fiber source such as straw. A roughage source able to satisfy calves' behavioral needs and to improve digestive processes without damaging the digestive apparatus still has to be identified.     

不同添加剂和日粮类型对黄牛瘤胃原虫计数影响的研究

以莫能霉素、盐霉素添加剂和自制的复合营养舔(饲)块饲喂本地黄牛,研究其对瘤胃原虫(Rumen protozoa)计数厦瘤胃pH值的影响。试验结果表明,黄牛日粮添加莫能霉素、盐霉素使瘤胃原虫数减少,而补喂舔(饲)块使原虫数增加。同时发现,喂稻草型日粮时,黄牛瘤胃原虫计数较放牧时少。研究我国养牛条件下原虫的作用对牛饲料添加剂、瘤胃调控制的利用具有重要意义。     

High calcium intake lowers apparent digestibility of energy in veal calves.

Veal calves aged 8 weeks were fed iso-energetic amounts of milk replacers with either a low (7.1 g of calcium/kg of air-dry diet) or a high concentration of calcium (11.6 g of calcium/kg of air-dry diet) for a period of 10 weeks. The extra calcium was added in the form of calcium formiate. Final body weight of the two dietary groups was similar. Faeces were collected during the final week of the trial. The high calcium diet raised faecal dry matter output by 87% and faecal energy by 70%. The extra output of faecal dry matter was composed of 36% and 37% of crude fat and ash, respectively. The extra faecal energy output was for 75% in the form of crude fat. The high versus low calcium intake not only depressed apparent digestibility of total lipids but also that of crude protein, carbohydrates and ash. It is concluded that a high calcium intake by veal calves reduced energy availability without affecting body weight gain.     

An evaluation of anthelmintic properties,assessed using faecal nematode egg counts,of New Zealand native flax (Phormium tenax)

AIM: To investigate the anthelmintic properties of New Zealand native flax (Phormium tenax) for cattle, using a faecal egg count reduction test (FECRT).

METHODS: Twenty-six heifer calves with high (>300 epg) faecal nematode egg counts (FEC) were paired into two groups and fed either chopped flax leaves ad libitum, or barley straw at an equivalent dry matter (DM) rate, from Day 0–7; all were supplemented with 1.5 kg/head/day cereal feed supplement. On Days 8–10, all heifers were fed a common diet of 3.5 kg DM/ head/day barley straw and 1.5 kg/head/day cereal feed supplement. Heifers were weighed and faecal samples were collected on Days —6, 0, 7, and 10; samples were analysed in triplicate for FEC. The nutritive value of the flax and straw was analysed.

RESULTS: Both the flax and straw had low dry matter digestibility (DMD) and protein content. Although the flax-fed claves grew more than the controls, this may have been related to gut fill. Total daily faecal egg output was similar for flax and straw groups on Day 7 (14.7 vs 15.0 x 10⁶ eggs/day, respectively) and Day 10 (14.9 vs 15.1 x 10⁶ eggs/day, respectively). There was no difference in the change in FEC with time between the calves fed flax or straw diets.

CONCLUSION: Consumption of flax leaves did not reduce FEC in calves with a mixed nematode infection.     

Effects of Supplementation of a Grass Silage and Barley Diet with Urea,Rapeseed Meal and Heat-moisture-treated Rapeseed Cake on Omasal Digesta Flow and Milk Production in Lactating Dairy Cows

Four multiparous dairy cows, fitted with rumen and duodenal cannulas, were fed grass silage and one of four concentrates of barley (B), barley+urea (BU), barley+solvent-extracted rapeseed meal (BRM) or barley+heat-moisture-treated rapeseed cake (BRC). Despite marginal N deficiencies for the control diet (B), BU did not affect milk yield, ruminal fibre digestion or omasal total non-ammonia-N (NAN) or microbial NAN flow. In contrast, BRM and BRC diets significantly increased milk and milk protein yields and omasal dietary NAN flows. Effects of rapeseed meal (RSM) and rapeseed cake (RSC) on milk yield and omasal NAN flow were similar. The diets had no effect on rumen microbial protein synthesis. In general, non-protein N and soluble true protein comprised 0.20 of omasal total NAN flow, for all diets. Supplementary AAT from rapeseed feeds appeared to escape from the rumen as insoluble feed particles.     

Control of coccidia in young calves using lasalocid

SUMMARY Thirty-six, 2- to 4-day-old Friesian bull calves were divided into 4 groups and fed milk replacer and calf starter pellets ad libitum in separate pens. Four treatments were applied; lasalocid in milk (1 mg/kg body weight/day) (M), lasalocid in starter (F), lasalocid in both milk and starter (M+F) and untreated (C). When the calves were about 2 weeks old they were each dosed orally with 550 000 sporulated Eimeria sp oocysts, mainly E zurneii and E bovis. The infection, detected by faecal excretion of oocysts, was suppressed in the M+F and M groups. There was significant excretion of oocysts in the F group but these calves did not show any clinical signs of coccidiosis. Untreated calves were affected with diarrhoea containing blood on the 24th day after inoculation. Body weight gain and intake of starter pellets was also depressed in the untreated calves during the time they were clinically affected. It is concluded that mixing lasalocid in milk replacer (or fresh milk) is an effective method of protecting young calves against early infection with coccidia.     

荷斯坦公犊牛生产小牛肉的研究进展

国外利用荷斯坦公犊牛乳饲、谷饲生产小牛肉的技术已经十分成熟,为满足我国消费者对高档牛肉日益增长的需求,借鉴国内外经验技术,合理利用我国丰富的奶公犊资源生产高附加值牛肉,既能提高奶牛养殖经济效益又能解决我国高档牛肉进口量逐年增加的问题。现从小牛肉的分类、荷斯坦公犊牛生产小牛肉品质的影响因素、生产犊牛白肉的犊牛代乳品研究、生产犊牛红肉的饲料日粮研究四方面展开综述,以期为我国利用荷斯坦公犊牛生产小牛肉技术提供参考。     

饲粮中添加牛至精油和莫能菌素对荷斯坦犊牛血清生化指标、消化酶活性及瘤胃微生物区系的影响

旨在研究牛至精油（oregano essential oil,OEO）与莫能菌素（monensin,MON）对荷斯坦犊牛血清生化指标、消化酶活性以及瘤胃微生物区系的影响。本试验前期阶段选用了体重相近（（41.31±2.23）kg）,体况良好的荷斯坦初生犊牛80头,随机分为4组,每组20头,采用单栏饲养。对照组饲喂全脂牛乳和颗粒饲料,其他3个试验组在饲喂全脂牛乳和颗粒饲料的基础上分别添加4 g·kg^-1牛至精油、3.6 g·kg^-1莫能菌素和7.6 g·kg^-1牛至精油和莫能菌素的混合物,饲喂至56、70日龄时,从每组中选取6头体重相近的公犊,颈静脉采血测定血清指标,并通过口腔导管的形式采集犊牛的瘤胃液,检测消化酶活性以及瘤胃微生物区系。结果表明：1）添加牛至精油显著提高了56日龄犊牛血清中TP、SOD、GSH和GSH-Px的浓度（P ≤ 0.05）;莫能菌素对56、70日龄犊牛BUN浓度有降低的趋势（P<0.10）。2）牛至精油显著降低了56、70日龄犊牛瘤胃中产琥珀酸丝状杆菌的数量（P<0.05）,显著提高了白色瘤胃球菌的数量（P ≤ 0.05）;莫能菌素显著降低了56、70日龄犊牛瘤胃中原虫的数量（P ≤ 0.05）,并有降低白色瘤胃球菌数量的趋势（P<0.10）,在56日龄时,莫能菌素有降低犊牛瘤胃中黄色瘤胃球菌数量的趋势（P<0.10）;牛至精油和莫能菌素对56、70日龄犊牛瘤胃中溶纤维丁酸弧菌有显著的交互作用（P ≤ 0.05）;在56日龄时,牛至精油和莫能菌素对栖瘤胃普雷沃氏菌有交互作用的趋势（P<0.10）,而在70日龄时则呈显著的交互作用（P ≤ 0.05）。3）牛至精油和莫能菌素对56、70日龄犊牛瘤胃中胃蛋白酶浓度有显著的交互作用（P ≤ 0.05）。综上所述,饲粮中添加牛至精油可提高犊牛的免疫力和抗氧化能力。莫能菌素在抑制瘤胃内原虫数量上强于牛至精油,牛至精油对提高主要蛋白质降解菌数量的作用效果优于莫能菌素。总之,牛至精油可改善犊牛的健康状况以及调控瘤胃微生物区系,牛至精油作为天然植物抗生素可替代犊牛期预防性治疗的其他类抗生素生长促进剂。     

Immune modulation by Ostertagia ostertagi and the effects of diet

IgG1 antibody responses to Ostertagia ostertagi third stage larvae (L3) and the third party antigen, keyhole limpet haemocyanin (KLH), and faecal egg counts were determined in calves infected with a single dose of O. ostertagi and in uninfected, pair-fed calves. The infected and uninfected calves were given diets either high (H) or low (L) in protein and energy. The diets were within the normal range of husbandry practice in the UK. IgG1 antibody responses to L3 antigen were significantly greater from 6 weeks post-infection in infected calves given the L diet than in infected calves given the H diet (P less than 0.05). The effects of diet and infection on anti-KLH IgG1 responses were independent of each other. IgG1 responses to KLH were decreased by infection and by the L diet compared with the H diet.     

Growth and parameters of microflora in intestinal and faecal samples of piglets due to application of a phytogenic feed additive

A commercial phytogenic feed additive (PFA), containing the fructopolysaccharide inulin, an essential oil mix (carvacrol, thymol), chestnut meal (tannins) and cellulose powder as carrier substance, was examined for effects on growth and faecal and intestinal microflora of piglets. Two experiments (35 days) were conducted, each with 40 male castrated weaned piglets. In experiment 1, graded levels of the PFA were supplied (A1: control; B1: 0.05% PFA; C1: 0.1% PFA; D1: 0.15% PFA) in diets based on wheat, barley, soybean meal and fish meal with lysine as the limiting amino acid. In experiment 2, a similar diet with 0.1% of the PFA (A2: control; B2: 0.1% PFA; C2: +0.35% lysine; D2: 0.1% PFA + 0.35% lysine) and lysine supplementation was utilized. During experiment 1, no significant effect of the PFA on growth, feed intake and feed conversion rate was observed (p > 0.05). Lysine supplementation in experiment 2 improved growth performance significantly, but no significant effect of the PFA was detected. Microbial counts in faeces (aerobes, Gram negatives, anaerobes and lactobacilli) during the first and fifth week did not indicate any significant PFA effect (p > 0.05). In addition, microflora in intestinal samples was not significantly modified by supplementing the PFA (p > 0.05). Lysine supplementation indicated lysine as limiting amino acid in the basal diet, but did not influence the microbial counts in faeces and small intestine respectively.