Effects of lighting source as an environmental strategy for heat stress amelioration in growing Californian rabbits during summer season

Growth performance, plasma metabolites, meat quality, and meat and lipid health indices of New Zealand White rabbits as affected by dietary dried tomato pomace powder supplementation during the summer season

One hundred and twenty New Zealand White rabbits (NZW) (5-week-old; 735.27 ± 27.23 g) were kept in an open-sided house during the summer season. The experiment aims to evaluate the impacts of dried tomato pomace powder (DTPP) supplementation on rabbits' performance, blood metabolites, carcass traits, meat quality, and lipid and health indices of NZW rabbits during 5-13 weeks of age. The four treatments were a standard rabbit feed (control) and the control diet supplemented with 0.5, 1.0, and 1.5% DTPP, respectively. Rabbits fed a diet containing 1.5% DTPP showed the highest growth rate through weeks 9-13 of age despite having the lowest feed intake spanning 5-13 weeks. The best feed conversion ratio (FCR) was recorded in rabbits fed with 1.5% DTPP-supplemented diet for 5-13 weeks. Diets supplemented with 0.5 or 1.0% DTPP enhanced markedly dressing %, total edible flesh, saturated (SFAs), monounsaturated (MUFAs), and polyunsaturated fatty acid (PUFAs) contents, as well as the ∑n - 6/∑n - 3 ratio and the total n - 6 of meat. Dietary supplementation with DTPP decreased kidney, abdominal, and back fat. Diets supplemented with DTTP decreased total cholesterol, triglycerides, and very low-density lipoprotein (vLDL) concentrations. The greatest levels of linoleic acid, arachidonic and water-holding capacity in meat were observed in rabbits fed 1.5% DTPP-supplemented diets. Diets containing 1 and 1.5% DTPP improved meats' atherogenic and thrombogenic indices, meat lipid quality desired fatty acids/undesired fatty acids ratio, and meat health index. Conclusively, DTPP up to 1.5% maintained the growth performance of rabbits, boosted meat quality through increasing vitamin E, reduced fat deposition, modified fatty acid composition, and improved atherogenic, thrombogenic, and hypocholesterolemic indices of rabbit meat.

Efficacy of ascorbic acid and different sources of orange peel on growth performance, gene expression, anti-oxidant status and microbial activity of growing rabbits under hot conditions

Orange peel and its extract are good sources of phenols and vitamin C that can be used as powerful antioxidants and antibacterial. The effects of dietary ascorbic acid (AA), orange peel powder (OPP) and orange peel extract (OPE) supplementations on growth performance, blood biochemicals, gene expression and antioxidant status of growing rabbits under hot conditions were investigated. A total of 80 weaned Giant Flander male rabbits, five weeks old (606.25 ± 10.08 g), were randomly assigned to four groups. The first group received untreated diet (control group). The other groups received diets supplemented with 0.5 g AA/kg diet, 2% OPP and 500 mg OPE/kg diet. The lowest feed conversion ratio (FCR) was recorded by rabbits consumed diet supplemented with AA. Supplementations of OPP and OPE reduced blood plasma total cholesterol, low density lipoprotein and very-low density lipoprotein concentrations. The tested diets reduced triglycerides, total lipids, hydrogen peroxide, malondialdehyde levels, Staphylococcus aureus and Escherichia coli of the rabbits cecum. Supplementation of OPE improved activities of superoxide dismutase gene (6.1475) and insulin-like growth factor-1 (9.2108). Conclusively, dietary supplementation of OPE improved rabbit performance through improving antioxidant enzyme activities as well as upregulation of insulin-like growth gene. Additionally, OPP and OPE (2% and 500 mg/kg diet, respectively) had antibacterial effects for growing rabbits under hot conditions.

Wet feed and chilled water as stratigies to ameliorate heat stress impacts in growing turkeys during summer conditions

The researchers investigated wet feed and chilled water effects on growth performance, carcass characteristics, and physiologic responses of native turkeys during the summer season. We hypothesized that the present treatments during the hot season would show different performances. A total of 180 four-week-old unsexed pullets were divided into six groups in a 3 × 2 factorial arrangement. Pullets were allocated regarding feed conditions to 3 groups (ad libitum dry feed, ad libitum wet feed, and diurnal wet feed). Each group was divided into 2 subgroups according to water temperature (ordinary or chilled water; 15-16 °C). Pullets fed diurnal wet feed and drank chilled water had the highest daily feed intake and the lowest feed conversion ratio during 4-16 weeks of age. Abdominal fat, IgG level and body temperature were low, whereas total antioxidant capacity and the meat quality scores for color, juiciness, and susceptibility were high in turkeys that drank chilled water. The interaction between wet feed and water temperature showed significant changes in glucose, cholesterol levels, and alanine transaminase activity. Pullets fed diurnal wet feed and drank chilled water had the lowest body temperatures. Wet feeding and chilled water may be the appropriate feeding method for native turkeys raised in hot weather.

Environmental heat stress in rabbits: implications and ameliorations

Profitable production of rabbit meat requires comfortable environment for expression of good quality traits embedded in the genetic components of rabbits. One of the major problems facing rabbit production is heat stress, especially in hot regions of the world. This is further aggravated by global warming being experienced as a result of climate change. Rabbits have no or few sweat glands, complicating the problem of heat dissipation, thereby predisposing the animals to heat stress (HS). Heat stress adversely affect welfare and adaptation, feed consumption and utilization, immunity and health status, growth, reproduction, and milk production in rabbits. Rabbits are homoeothermic animals. They should be capable of body temperature regulation within a narrow range. Thermoregulation is extremely poor in rabbits because of lack of sweat glands. Rabbits are highly sensitive to high ambient temperature. The presence of thick insulator fur on the skin further impedes heat loss in rabbits. This review summarizes data available literatures in the last two decades (2000-2020). Short compilation on management techniques adopted in rearing rabbits under hot conditions is included.

Early heat acclimation during incubation improves Japanese quail performance under summer conditions

Effects of exposing quail eggs to high temperature on the heat tolerance ability and productivity of birds were investigated. Four groups of 600 fertile eggs were randomly selected; the first group was incubated under 37.5 °C and the hatched chicks were reared under a gradual decrease in temperature from 35 to 24 °C (Control). The second group was exposed to 39.1 °C for 2 h/day during 4-14 days of embryogenesis and the hatched chicks were reared under a gradual decrease in temperature from 35 to 24 °C. The third group was incubated under 37.5 °C and the hatched chicks were exposed to 39 ± 1 °C for 2 h/day during 4-14 days of age. The fourth group was exposed to 39 ± 1 °C for 2 h during 4-14 days of embryogenesis and the hatched chicks were exposed to 39 ± 1 °C for 2 h/day during 4-14 days of age. The temperature applied changed (P < 0.01) embryo weight and incubation period. Birds exposed to high temperature during brooding had superior growth performance, dressed carcass, body temperature and health traits. Birds subjected to 39 ± 1 °C during brooding exhibited decreased feed consumption and body weight gain. Finally, this work suggests that thermal acclimation during embryogenesis might offer a practical method for easing heat stress.