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Global protein shortages and sustainability concerns have increased consumer demand for non-animal-derived protein. Dried whole-cell yeast (Saccharomyces cerevisiae) may be a suitable alternative to rendered protein meals in pet foods. The objective of this study was to investigate the effects of dried yeast in dog and cat foods on indicators that pet parents typically use to evaluate the suitability of a food for their pet. For this evaluation, two dog and two cat dry extruded diets were formulated. For each species, the test diet contained 10% dried yeast (Yeast) and the control diet was devoid of yeast (Control). Palatability, apparent total tract nutrient digestibility, and fecal quality of the foods were assessed in dogs and cats. Urine pH and specific gravity were measured in cats as indicators of urinary tract health. In dogs, the Yeast diet showed equivalent or better palatability compared to the Control diet based on total food consumption (P  = 0.06), average daily consumption (day 1, P  = 0.10; day 2, P  = 0.54), and first choice preference over 2 consecutive days (P  = 0.005). Cats showed a strong preference for the Yeast diet with more than double the consumption during the 2-d test period (P  = 0.001). More cats showed a first-choice preference for the Yeast diet (24 vs. 16), but the difference was not statistically significant (P  = 0.21). There were no significant differences in stool quality or nutrient digestibility when fed Yeast vs. Control diets to the dogs and cats (P  > 0.05). All cats produced urine with pH and specific gravity values within the normal range, though specific gravity was lower in the Control group (P  = 0.003). This study provides support for the acceptability and digestibility of dog and cat diets containing dried yeast as an alternative protein source. [ABSTRACT FROM AUTHOR]

Leury, Brian J., Lance H. Baumgard, Stephanie S. Block, Nthabisheng Segoale, Richard A. Ehrhardt, Robert P. Rhoads, Dale E. Bauman, Alan W. Bell, and Yves R. Boisclair. Effect of insulin and growth hormone on plasma leptin in periparturient dairy cows. Am J Physiol Regul Integr Comp Physiol 285: R1107-R1115, 2003. First published July 24, 2003; 10.1152/ajpregu.00320.2003.--After parturition, dairy cows suffer from an intense energy deficit caused by the onset of copious milk secretion and an inadequate increase in voluntary food intake. We previously showed that this energy deficit contributes to a decline in plasma leptin. This decline mirrors that of plasma insulin but is reciprocal to the profile of plasma growth hormone (GH), suggesting that both hormones may regulate plasma leptin in periparturient dairy cows. To study the role of insulin, hyperinsulinemic-euglycemic clamps were performed on six dairy cows in late pregnancy (LP, 31 days prepartum) and early lactation (EL, 7 days postpartum). Infusion of insulin (1 [micro]g.kg body [wt.sup.-1].[h.sup.-1]) caused a progressive rise in the plasma concentration of leptin that reached maximum levels at 24 h during both physiological states. At steady states, the absolute increase in plasma leptin was greater in LP than in EL cows (2.4 vs. 0.4 ng/ml). Insulin infusion increased leptin mRNA in adipose tissue during LP but not during EL. During lactation, mammary epithelial cells expressed leptin mRNA but insulin did not increase milk leptin output. In contrast, a 3-day period of GH administration had no effect on plasma leptin during LP or EL. Therefore, insulin increases plasma leptin in LP by stimulating adipose tissue synthesis but has only marginal effects in EL, when cows are in negative energy balance. Other factors, such as increased response of adipose tissue to [beta]-adrenergic signals, probably contribute to the reduction of plasma leptin in early lactating dairy cows. pregnancy; lactation; hyperinsulinemic-euglycemic clamp

The algae Dunaliella bardawil and Dunaliella salina naturally contain large concentrations of all-trans and 9-cis [Beta]-carotene ([Beta]C). The purpose of this study was to compare the relative serum and tissue accumulation of all-trans and 9-cis [Beta]C in ferrets fed different ratios of all-trans/9-cis [Beta]C derived from two commercial sources, D. bardawil or D. salina (Betatene). Male ferrets (7 wk old) were fed carotene-free, pelleted diets for 27 d. Beginning on d 18, groups of ferrets (n = 6 or 7) received daily, one of six oral supplements varying in ratios of 9-cis and all-trans [Beta]C mixed with [approximately]1.0mL of Ensure. Four supplements containing 5.2-8.3 [micro]mol total [Beta]C were prepared from a 20% Betatene preparation, D. bardawil, a high-cis Betatene preparation, and Betatene further enriched in 9-cis [Beta]C with all-trans [Beta]C/9-cis [Beta]C ratios of 2.2, 1.5, 0.6 and 0.4, respectively. Two control supplements, high and low [Beta]C, were prepared from commercial [Beta]C beadlets. The high control supplement had an all-trans/9-cis ratio of 19.0, whereas 9-cis [Beta]C was not detected in the low supplement. On d 27, serum and tissues were obtained for HPLC analysis of [Beta]C and its isomers. Analysis of livers showed that all-trans [Beta]C was the primary isomer present, but 9-cis and other isomers were also detected in all groups. The hepatic all-trans/9-cis ratios were 5.9, 4.9, 2.5, 1.4, 52.2 and 47.5, respectively, for the groups listed above. Lower amounts of all-trans and 9-cis [Beta]C were found in kidneys compared with the liver, but ratios of all-trans/9-cis were not different among groups. Only trace amounts of 9-cis [Beta]C were found in serum. These results demonstrate that the algae D. bardawil and D. salina provide a bioavailable source of [Beta]C isomers, but, as in humans, absorption of 9-cis [Beta]C is poor and any 9-cis [Beta]C absorbed is apparently cleared by the liver. KEY WORDS: * 9-cis [Beta]-carotene * domestic ferrets * carotenoids * all-trans [Beta]-carotene

At parturition, dairy cows experience a 70% reduction in plasma IGF-I. This reduction coincides with decreased abundance of GHR1A, the liver-specific transcript of the growth hormone receptor (GHR) gene, suggesting impaired growth hormone-dependent synthesis of IGF-I. It is not immediately obvious that the periparturient reduction in GHR1A is sufficient to reduce hepatic GHR abundance. This is because approximately 50% of total GHR mRNA abundance in prepartum liver is accounted for by ubiquitously expressed transcripts which remain collectively unchanged at parturition. In addition, the possibility that parturition alters GHR expression in other growth hormone target tissue has not been examined. To address these questions, we measured GHR gene expression and GHR protein in liver and skeletal muscle of four dairy cows on days -35,+3 and+56 (relative to parturition on day 0). Hepatic GHR abundance and GHR1A transcripts were lower on day+3 than on day -35 and returned to late pregnancy value by day+56. Additional studies in two other groups of cows indicated that the hepatic levels of the GHR protein recovered substantially within 10 days after parturition. These changes occurred without variation in the abundance of HNF4, a liver-enriched transcription factor activating the promoter responsible for GHR1A synthesis. In contrast to liver, levels of GHR gene expression and GHR protein were identical on days -35,+3 and+56 in skeletal muscle. These data suggest a role for the GHR in regulating tissue-specific changes in growth hormone responsiveness in periparturient dairy cows.