Carotenoids provide pigmentation to avian species, and also have immunomodulatory potential, although experimental results are often inconsistent. Therefore, dietary carotenoid deposition into immune tissue of growing chicks was examined in relation to their maternal carotenoid status (i.e., yolk carotenoid level). Single-comb white leghorn chicks were hatched from carotenoid-replete (C+) or carotenoid-deplete (C-) eggs. For 4 wk posthatch, chicks were fed diets whose carotenoid level ranged from 0 to 38 mg total carotenoid/kg. Carotenoid additions consisted of lutein + canthaxanthin at a ratio of 4:1. After 4 wk, the carotenoid concentration of thymus, bursa, liver, plasma and shank epithelium was measured by HPLC. Egg yolk-derived carotenoids were detectable in chicks fed 0 dietary carotenoids for 4 wk. Chicks hatched from C+ eggs had significantly greater tissue lutein, zeaxanthin and/or canthaxanthin for all tissues (P < 0.05), compared to chicks hatched from C- eggs. Only bursa carotenoids were not dependent on chick diet (P = 0.24); for all other tissues, C+ chicks incorporated dietary carotenoids in a dose-dependent manner (P < 0.01), whereas C- chicks never achieved the same level of carotenoid incorporation. This study demonstrated the importance of maternal carotenoid status on incorporation of yolk- and diet-derived tissue carotenoids in an avian model, and may explain some variability in carotenoid-based research, given that maternal carotenoid status is rarely controlled.

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Lutein, a dihydroxycarotenoid, has antioxidant and immunomodulatory potential. Two 2 x 2 x 2 factorial designs examined effects of carotenoids during in ovo embryogenesis and, in the diet posthatch, on the systemic inflammatory response to lipopolysaccharide (LPS). In both trials, breeder hens were fed a carotenoid-replete (40 mg lutein/kg) or a carotenoid-deplete diet, eggs were collected, and chicks were hatched from carotenoid-deplete or carotenoid-replete eggs. Meat-type chicks (n = 160 and n = 144, respectively) were then fed diets containing 0 or 40 mg lutein/kg diet and either injected or not injected with LPS. LPS injection increased plasma haptoglobin and Zn (P < 0.01) and reduced plasma Fe and Cu (P < 0.01). Chicks hatched from carotenoid-deplete eggs had greater changes in plasma Fe and S post-LPS than chicks hatched from carotenoid-replete eggs (P < 0.05 for each). Compared with chicks fed 40 mg lutein/kg diet, chicks fed 0 mg lutein had greater body weight losses and higher plasma haptoglobin and relative thymus, bursa, and spleen weights post-LPS (P < 0.05). Data suggest that a lack of carotenoid exposure, either in ovo or posthatch, increases parameters of systemic inflammation.

Two studies were conducted simultaneously and evaluated the Thr needs of male Ross × Ross 708 broilers. Broilers in the 2 studies were reared under 2 litter conditions: new (NL) vs. used built-up soft wood shavings (BL). Separated by a center aisle, all floor pens from 1 side of the close-sided house contained NL, whereas the opposite side contained BL. Broilers received common diets up to 21 d and then were fed 1 of 6 total dietary Thr levels that ranged from 0.51 to 0.86% total Thr until d 42. At 42 d, birds were processed. A subsample of birds from each experimental unit corresponding to either the 0.51 or 0.72% Thr treatments was taken, immune function was quantified, and lymphoid organs were weighed. Results for live performance and carcass traits are in close agreement with previously reported values in the literature. Quadratic responses were observed for BW gain, feed conversion, and carcass and breast meat absolute and relative weights. Depending on the variable, these responses were maximized from 0.71 to 0.74% Thr when broilers were raised on NL and from 0.73 to 0.78% Thr when broilers were raised on BL. Low Thr (0.51%) was without effect on most immune parameters. However, low Thr decreased relative thymus weight and increased monocyte NO production in built-up and new litter environments, respectively.

Amphibian biology is intricate, and there are many inter-related factors that need to be understood before establishing successful Conservation Breeding Programs (CBPs). Nutritional needs of amphibians are highly integrated with disease and their husbandry needs, and the diversity of developmental stages, natural habitats, and feeding strategies result in many different recommendations for proper care and feeding. This review identifies several areas where there is substantial room for improvement in maintaining healthy ex situ amphibian populations specifically in the areas of obtaining and utilizing natural history data for both amphibians and their dietary items, achieving more appropriate environmental parameters, understanding stress and hormone production, and promoting better physical and population health. Using a scientific or research framework to answer questions about disease, nutrition, husbandry, genetics, and endocrinology of ex situ amphibians will improve specialists’ understanding of the needs of these species. In general, there is a lack of baseline data and comparative information for most basic aspects of amphibian biology as well as standardized laboratory approaches. Instituting a formalized research approach in multiple scientific disciplines will be beneficial not only to the management of current ex situ populations, but also in moving forward with future conservation and reintroduction projects. This overview of gaps in knowledge concerning ex situ amphibian care should serve as a foundation for much needed future research in these areas.