Over the past decades several studies have investigated the importance of an adequate vitamin E status to sustain both animal health and production in dairy cows. Cow milk is considered as a remarkable source of bioac...Over the past decades several studies have investigated the importance of an adequate vitamin E status to sustain both animal health and production in dairy cows. Cow milk is considered as a remarkable source of bioactive components promoting human health, which has renewed interest in the effects of vitamin E supplementation on its nutritional value, sensory quality and shelf life. Thus, defining relative bioavailability, utilisation and transfer into milk of different vitamin E formulations is particularly important to assess the adequate levels of supplementation for animal health and milk quality. In nature vitamin E is present under one isomeric form, RRR α-tocopherol;when α-tocopherol is synthesized chemically, a racemic mixture of 8 possible isomers of α-tocopherol in equimolar concentrations is produced (all-rac α-tocopherol). The different stereoisomers have different biopotencies in humans and livestock;the conversion factor between RRR and all-rac vitamin E was estimated by early studies on the basis of the rat foetal resorption bioassay, and then extended to other species. Recent advances on the distribution of vitamin E stereoisomers in plasma and tissues have highlighted the need to formulate new conversion factors in dairy cows as well as in humans. On account of this, the present article aims to consider past and recent data related to vitamin E in dairy cow nutrition.展开更多
Escherichia coli diarrhoea is a multifactorial condition which usually occurs during the post-weaning and is responsible for economic losses in pig production. One approach, to evaluate if substitute of antibiotic in ...Escherichia coli diarrhoea is a multifactorial condition which usually occurs during the post-weaning and is responsible for economic losses in pig production. One approach, to evaluate if substitute of antibiotic in vivo is effective in controlling postweaning diarrhea in the gastrointestinal tract ecosystem, is to use an appropriate disease model. However, there are still many criticisms related to the incidence and the severity of the diarrhoea in the experimental conditions. The aim of the study was to set up an Escherichia coli challenge model in order to induce a significant percentage of diarrhoea in weaned piglets for the evaluation of innovative compounds in vivo. A total of 35 piglets, weaned at 33±2 days were randomized into 3 groups: control (CG), infected 1 (IG1) and infected 2 (IG2). One day after arrival piglets of IG1 and IG2 were orally inoculated with 3.7 × 108 CFU of Escherichia coli O149. All piglets were fed a high protein ration for 3 days. Daily health status and faeces were recorded by a point scale individually. Challenge strains in faecal samples were evaluated by polymerase chain reaction, serotyping and biochemical identification. Diarrhoea was observed in 96.67% (58.6% severe;41.4% mild) of all infected piglets and occurred on average 1.3 days after the challenge. The CG group presented one piglet with a transient mild diarrhoea. The E. coli challenge significantly affected the consistency and color of faeces (P E. coli O149, mainly hemolytic (88%), was isolated in 56% of faecal samples and the 70% of piglets with severe diarrhoea shed E. coli O149 in the faeces. Zootechnical parameters did not show significant differences. The experimental conditions described in this study allowed to effectively induce diarrhoea in weaned piglets. In conclusion a multifactorial approach (infectious, nutritional and management) is necessary to reproduce in vivo diarrhea in piglets.展开更多
文摘Over the past decades several studies have investigated the importance of an adequate vitamin E status to sustain both animal health and production in dairy cows. Cow milk is considered as a remarkable source of bioactive components promoting human health, which has renewed interest in the effects of vitamin E supplementation on its nutritional value, sensory quality and shelf life. Thus, defining relative bioavailability, utilisation and transfer into milk of different vitamin E formulations is particularly important to assess the adequate levels of supplementation for animal health and milk quality. In nature vitamin E is present under one isomeric form, RRR α-tocopherol;when α-tocopherol is synthesized chemically, a racemic mixture of 8 possible isomers of α-tocopherol in equimolar concentrations is produced (all-rac α-tocopherol). The different stereoisomers have different biopotencies in humans and livestock;the conversion factor between RRR and all-rac vitamin E was estimated by early studies on the basis of the rat foetal resorption bioassay, and then extended to other species. Recent advances on the distribution of vitamin E stereoisomers in plasma and tissues have highlighted the need to formulate new conversion factors in dairy cows as well as in humans. On account of this, the present article aims to consider past and recent data related to vitamin E in dairy cow nutrition.
文摘Escherichia coli diarrhoea is a multifactorial condition which usually occurs during the post-weaning and is responsible for economic losses in pig production. One approach, to evaluate if substitute of antibiotic in vivo is effective in controlling postweaning diarrhea in the gastrointestinal tract ecosystem, is to use an appropriate disease model. However, there are still many criticisms related to the incidence and the severity of the diarrhoea in the experimental conditions. The aim of the study was to set up an Escherichia coli challenge model in order to induce a significant percentage of diarrhoea in weaned piglets for the evaluation of innovative compounds in vivo. A total of 35 piglets, weaned at 33±2 days were randomized into 3 groups: control (CG), infected 1 (IG1) and infected 2 (IG2). One day after arrival piglets of IG1 and IG2 were orally inoculated with 3.7 × 108 CFU of Escherichia coli O149. All piglets were fed a high protein ration for 3 days. Daily health status and faeces were recorded by a point scale individually. Challenge strains in faecal samples were evaluated by polymerase chain reaction, serotyping and biochemical identification. Diarrhoea was observed in 96.67% (58.6% severe;41.4% mild) of all infected piglets and occurred on average 1.3 days after the challenge. The CG group presented one piglet with a transient mild diarrhoea. The E. coli challenge significantly affected the consistency and color of faeces (P E. coli O149, mainly hemolytic (88%), was isolated in 56% of faecal samples and the 70% of piglets with severe diarrhoea shed E. coli O149 in the faeces. Zootechnical parameters did not show significant differences. The experimental conditions described in this study allowed to effectively induce diarrhoea in weaned piglets. In conclusion a multifactorial approach (infectious, nutritional and management) is necessary to reproduce in vivo diarrhea in piglets.
