Stable hydrogen isotope methodology is used in nutrition studies to measure growth, breast milk intake, and energy requirement. Isotope ratio MS is the best instrumentation to measure the stable hydrogen isotope ratios in physiological fluids. Conventional methods to convert physiological fluids to hydrogen gas (H₂) for mass spectrometric analysis are labor intensive, require special reagent, and involve memory effect and potential isotope fractionation. The objective of this study was to determine the accuracy and precision of a platinum catalyzed H₂-water equilibration method for stable hydrogen isotope ratio measurements. Time to reach isotopic equilibrium, day-to-day and week-to-week reproducibility, accuracy, and precision of stable hydrogen isotope ratio measurements by the H₂-water equilibration method were assessed using a Thermo DELTA V Advantage continuous-flow isotope ratio mass spectrometer. It took 3 h to reach isotopic equilibrium. The day-to-day and week-to-week measurements on water and urine samples with natural abundance and enriched levels of deuterium were highly reproducible. The method was accurate to within 2.8 ^o/oo and reproducible to within 4.0 ^o/oo based on analysis of international references. All the outcome variables, whether in urine samples collected in 10 doubly labeled water studies or plasma samples collected in 26 body water studies, did not differ from those obtained using the reference zinc reduction method. The method produced highly accurate estimation on ad libitum energy intakes, body composition, and water turnover rates. The method greatly reduces the analytical cost and could easily be adopted by laboratories equipped with a continuous-flow isotope ratio mass spectrometer.

Heat tolerance can be improved by feed restriction in broiler chickens. It is unknown whether the same is true for broiler breeders, which are restri

Heat stress due to high environmental temperature negatively influences animal performances. To better understand the biological impact of heat stress, laying broiler breeder chickens were subjected either to acute (step-wisely increasing temperature from 21 to 35°C within 24 hours) or chronic (32°C for 8 weeks) high temperature exposure. High temperature challenges significantly elevated body temperature of experimental birds (P<0.05). However, oxidation status of lipid and protein and expression of heat shock transcription factors (HSFs) and heat shock proteins (HSPs) 70 and 90 were differently affected by acute and chronic treatment. Tissue-specific responses to thermal challenge were also found among heart, liver and muscle. In the heart, acute heat challenge affected lipid oxidation (P = 0.05) and gene expression of all 4 HSF gene expression was upregulated (P<0.05). During chronic heat treatment, the HSP 70 mRNA level was increased (P<0.05) and HSP 90 mRNA (P<0.05) was decreased. In the liver, oxidation of protein was alleviated during acute heat challenge (P<0.05), however, gene expression HSF2, 3 and 4 and HSP 70 were highly induced (P<0.05). HSP90 expression was increased by chronic thermal treatment (P<0.05). In the muscle, both types of heat stress increased protein oxidation, but HSFs and HSPs gene expression remained unaltered. Only tendencies to increase were observed in HSP 70 (P = 0.052) and 90 (P = 0.054) gene expression after acute heat stress. The differential expressions of HSF and HSP genes in different tissues of laying broiler breeder chickens suggested that anti-heat stress mechanisms might be provoked more profoundly in the heart, by which the muscle was least protected during heat stress. In addition to HSP, HSFs gene expression could be used as a marker during acute heat stress.

The neonatal pig ranks among the most prominent research models for the study of pediatric nutrition and metabolism. Its precocial development at birth affords ready adaptation to artificial rearing systems, and research using this model spans a wide array of nutrients. Sophisticated in vitro and in vivo methodologies supporting both invasive, reduction-science research as well as whole-animal preclinical investigations have been developed. Potential applications may dually benefit both agricultural and medical sciences (e.g., “agrimedical research”). The broad scope of this review is to outline the fundamental elements of the piglet model and to highlight key aspects of relevance to various macronutrients, including lipids, carbohydrates, proteins/amino acids, and calcium/phosphorus. The review examines similarities between piglets and infants and also piglet idiosyncrasies, concluding that, overall, the piglet represents an adaptable and robust model for pediatric nutrition and metabolism research.

The objective of this study was to investigate the effects of dietary supplemental Zn on growth performance, carcass traits, and meat quality of broilers. Dietary treatments included the corn-soybean meal-based diet (control) and the basal diet supplemented with 60, 120, or 180 mg of Zn/kg as ZnSO(4), Zn amino acid A, Zn proteinate B, or Zn proteinate A. The results showed that birds fed diets supplemented with Zn had higher ADFI, ADG, and percentage of eviscerated yield than birds fed the control diet. Supplemental Zn significantly increased the redness value in breast muscle and pH values in thigh muscle, decreased shear force in thigh muscle, and decreased drip loss in breast and thigh muscle. The DM and intramuscular fat contents of the breast muscle in broilers fed diets with supplemental Zn were higher than those of the control. Results from this study indicated that Zn could promote growth and improve production performance of broilers independent of Zn source.