Immune system activation begins a host of physiological responses. Infectious agents are recognized by monocytes and macrophages which in turn stimulate cytokine production. It is the hormone-like factors called cytok...Immune system activation begins a host of physiological responses. Infectious agents are recognized by monocytes and macrophages which in turn stimulate cytokine production. It is the hormone-like factors called cytokines that orchestrate the immune response. The classic responses observed with immune system activation and cytokine production include： anorexia, fever, lethargy, recruitment of other immune cells, and phagocytosis. While production of immune system components is known to require some amino acids, increases in amino acid requirements are more than offset by the associated decrease in protein accretion and increased muscle protein degradation that also accompanies immune system activation. However, the biggest impact of cytokine production is a decrease in feed intake. Therefore, as feed intake decreases, the energy needed to drive protein synthesis is also decreased. This suggests that diets should still be formulated on a similar calorie：lysine ratio as those formulated for non-immune challenged pigs. The evidence is sparse or equivocal for increasing nutrient requirements during an immune challenge. Nutritionists and swine producers should resist the pressure to alter the diet, limit feed, or add expensive feed additives during an immune challenge. While immune stimulation does not necessitate changes in diet formulation, when pigs are challenged with non-pathogenic diarrhea there are potential advantages on gut health with the increased use of crystalline amino acids rather than intact protein sources （i.e., soybean meal）. This is because reducing crude protein decreases the quantity of fermentable protein entering the large intestine, which lowers post weaning diarrhea. It also lowers the requirement for expensive specialty protein sources or other protein sources such as soybean meal that present immunological challenges to the gut. The objective of this review is two-fold. The first is to discuss immunity by nutrition interactions, or lack thereof, and secondly, to review amino acid requirement estimates for nursery pigs.展开更多
Biosecurity measures are essential for protecting pig health, however, these practices are not always utilized by smallholder farmers in Cambodia. This study aimed to assess the knowledge and practices, in terms of pi...Biosecurity measures are essential for protecting pig health, however, these practices are not always utilized by smallholder farmers in Cambodia. This study aimed to assess the knowledge and practices, in terms of pig biosecurity measures, of individual stakeholders involved in pig production in rural and peri-urban households in Cambodia. A survey tool was developed and administered using Kobotoolbox, an online electronic survey tool. Surveys were conducted in the provinces of Kampong Thom, Siem Reap, and Battambang during December 2017 to September 2018. There were 225 pig farmers, 43 village animal health workers (VAHWs), 3-district veterinarians (DVs), and 81 feed store owners enrolled in the study. Results showed that several biosecurity guidelines are not followed or well understood by farmers. Specific concerning practices included using natural boars, sharing pig equipment (e.g. scales), feeding kitchen waste, managing other livestock, handling manure, and not restricting access by visitors (VAHWs or DVs, boar owners, pig buyers, neighbors, and meat sellers). Thus, education of pig smallholder farmers and VAHWs on pig biosecurity is needed for improving pig health and production, economic value, and livelihood of smallholder farmers in Cambodia.展开更多
文摘Immune system activation begins a host of physiological responses. Infectious agents are recognized by monocytes and macrophages which in turn stimulate cytokine production. It is the hormone-like factors called cytokines that orchestrate the immune response. The classic responses observed with immune system activation and cytokine production include： anorexia, fever, lethargy, recruitment of other immune cells, and phagocytosis. While production of immune system components is known to require some amino acids, increases in amino acid requirements are more than offset by the associated decrease in protein accretion and increased muscle protein degradation that also accompanies immune system activation. However, the biggest impact of cytokine production is a decrease in feed intake. Therefore, as feed intake decreases, the energy needed to drive protein synthesis is also decreased. This suggests that diets should still be formulated on a similar calorie：lysine ratio as those formulated for non-immune challenged pigs. The evidence is sparse or equivocal for increasing nutrient requirements during an immune challenge. Nutritionists and swine producers should resist the pressure to alter the diet, limit feed, or add expensive feed additives during an immune challenge. While immune stimulation does not necessitate changes in diet formulation, when pigs are challenged with non-pathogenic diarrhea there are potential advantages on gut health with the increased use of crystalline amino acids rather than intact protein sources （i.e., soybean meal）. This is because reducing crude protein decreases the quantity of fermentable protein entering the large intestine, which lowers post weaning diarrhea. It also lowers the requirement for expensive specialty protein sources or other protein sources such as soybean meal that present immunological challenges to the gut. The objective of this review is two-fold. The first is to discuss immunity by nutrition interactions, or lack thereof, and secondly, to review amino acid requirement estimates for nursery pigs.
文摘Biosecurity measures are essential for protecting pig health, however, these practices are not always utilized by smallholder farmers in Cambodia. This study aimed to assess the knowledge and practices, in terms of pig biosecurity measures, of individual stakeholders involved in pig production in rural and peri-urban households in Cambodia. A survey tool was developed and administered using Kobotoolbox, an online electronic survey tool. Surveys were conducted in the provinces of Kampong Thom, Siem Reap, and Battambang during December 2017 to September 2018. There were 225 pig farmers, 43 village animal health workers (VAHWs), 3-district veterinarians (DVs), and 81 feed store owners enrolled in the study. Results showed that several biosecurity guidelines are not followed or well understood by farmers. Specific concerning practices included using natural boars, sharing pig equipment (e.g. scales), feeding kitchen waste, managing other livestock, handling manure, and not restricting access by visitors (VAHWs or DVs, boar owners, pig buyers, neighbors, and meat sellers). Thus, education of pig smallholder farmers and VAHWs on pig biosecurity is needed for improving pig health and production, economic value, and livelihood of smallholder farmers in Cambodia.
