All animals face the possibility of limitations in food resources that could ultimately lead to starvation-induced mortality. The primary goal of this review is to characterize the various physiological strategies that allow different animals to survive starvation. The ancillary goals of this work are to identify areas in which investigations of starvation can be improved and to discuss recent advances and emerging directions in starvation research. The ubiquity of food limitation among animals, inconsistent terminology associated with starvation and fasting, and rationale for scientific investigations into starvation are discussed. Similarities and differences with regard to carbohydrate, lipid, and protein metabolism during starvation are also examined in a comparative context. Examples from the literature are used to underscore areas in which reporting and statistical practices, particularly those involved with starvation-induced changes in body composition and starvation-induced hypometabolism can be improved. The review concludes by highlighting several recent advances and promising research directions in starvation physiology. Because the hundreds of studies reviewed here vary so widely in their experimental designs and treatments, formal comparisons of starvation responses among studies and taxa are generally precluded; nevertheless, it is my aim to provide a starting point from which we may develop novel approaches, tools, and hypotheses to facilitate meaningful investigations into the physiology of starvation in animals.

Starvation physiology: reviewing the different strategies animals use to survive a common challenge.

Effects of supplementation of canola meal-based diets with arginine on performance, plasma nitric oxide, and carcass characteristics of broiler chickens grown at high altitude

The phenomenon of fat deposition in broiler chickens is reviewed. The increase in growth rate through genetic selection in broiler chickens has been associated with increased fat deposition. Abdominal and subcutaneous fat are regarded as the main sources of waste in the slaughterhouse. On the other hand, a minimum quantity of intramuscular fat is necessary for an optimal sensory quality because of its positive influence on succulence and tenderness, flavor. In order to elucidate factors affecting the phenomenon and ways to decrease it a great deal of time and expense has gone into research. Results indicate that genotype, sex, age and nutrition of the broiler chicken are some of the main factors affecting fat deposition. Selection can reduce excessive fat deposition in the long term strategy and for reduced body fat deposition, either using abdominal fat content or plasma very-low-density-lipoprotein has been shown to be useful in reducing fat deposition. Also, selection for improved feed conversion ratio also can be used. Reports showed that feed restriction could be a way for reducing body fat, nevertheless, reports are contradicted. Ambient temperature is one of the most remarkable factors among the environmental parameters on fat deposition in broiler chicken. The factor having greatest effect on fat deposition in broiler chicken is the ratio of dietary protein to energy. The use of these concepts to address problem associated with early life fast growth rate require more studies of the nutrition of broiler chicken during the rearing period as well as more studies of the effect of selection against fatness on live performance broiler chicken.

Fat deposition in the broiler chicken: a review.

Low-fiber alfalfa (Medicago sativa L.) meal in the laying hen diet: Effects on productive traits and egg quality

The effects of feed restriction and ambient temperature on growth and ascites mortality of broilers reared at high altitude

The present study was conducted to evaluate the effects of a skip-a-day feed removal early in life on physiological parameters and ascites occurrence in broilers reared at a high altitude (2100 m above sealevel) under regular or cold temperatures. Three hundred 1-day-old male broilers were divided into two equal groups. One group was placed in an enclosure with standard thermal management. The other group treated for the induction of ascites was raised under cold temperature conditions. In each enclosure, birds were randomly assigned to one of two treatment groups (three replicate floor pens of 25 chicks per treatment group): (i) a control was fed a standard starter and grower diet according to the National Research Council; or (ii) a skip-a-day feed removal, which was similar to the control except for 24 h fasting intervals at 9, 11 and 13 days of age. Results indicate that live bodyweight following the feed removal at up to 42 days of age was significantly different between the control and skip-a-day restricted birds (P < 0.01). Skip-a-day feed removal resulted in decreased weight gain (P = 0.005) but did not influence feed conversion ratio. The heterophil : lymphocyte ratio was numerically higher for the cold environment and increased when birds were exposed to fasting, but these differences were not significant. Hematocrit was significantly higher (P = 0.0001) in broilers raised in cold conditions whereas it was not influenced by feed restriction. Circulatory thyroid hormone concentrations were not influenced by the feed restriction program under both environments. Birds subjected to cold had significantly lower (P = 0.0023) carcass yield compared to those reared at normal temperature. Breast yield and abdominal fat deposition were not influenced by cold or feed restriction. A reduction in mortality from ascites was noted in broilers who experienced early skip-a-day feed removal under both environmental conditions.

Application of an early skip-a-day feed restriction on physiological parameters, carcass traits and development of ascites in male broilers reared under regular or cold temperatures at high altitude

Ebrahim Asadi-Khoshoei

Papers

Application of an early skip-a-day feed restriction on physiological parameters, carcass traits and development of ascites in male broilers reared under regular or cold temperatures at high altitude