Our observations are consistent with the hypothesis that energy restriction reduces prostate tumor growth by inhibiting tumor angiogenesis. Furthermore, dietary fat concentration does not influence prostate tumor growth when energy intake is reduced.

Zinc is an essential nutrient that is required in humans and animals for many physiological functions, including immune and antioxidant function, growth and reproduction. Many aspects of zinc deficiency-induced anorexia have been well studied in experimental animals, most notably the laboratory rat. There is evidence that suggests zinc deficiency may be intimately involved with anorexia in humans: if not as an initiating cause, then as an accelerating or exacerbating factor that may deepen the pathology of the anorexia. The present review describes recent research investigating the relationship between zinc deficiency and the regulation of food intake, along with advances in the understanding of the food intake and body weight regulation systems. For more comprehensive reviews of zinc nutrition and zinc deficiency, readers are referred to the other reviews in this volume and the review text of Mills (1989). An excellent review focused solely on zinc status and food intake has been presented by O'Dell and Reeves (1989).

The nutritional regulation of intestinal adaptation extends beyond the route of nutrient administration as specific nutrients are known to mediate the adaptive response. Dietary carbohydrates are known to enhance intestinal adaptation in patients with short-bowel syndrome. This review discusses SCFA-induced adaptation in intestinal structure and function in adult rat and neonatal piglet models. Potential mechanisms relate to the salvage of energy as SCFA in the colon, direct mediation of intestinal adaptation by SCFA and stimulated release of glucagon-like peptide-2 (GLP-2) from enteroendocrine L cells by SCFA. Among the produced SCFA, butyrate appears to be responsible for increasing plasma GLP-2 concentration, in addition to the enterotrophic effects. Emerging evidence reveals that physiological concentrations of butyrate acutely upregulate the expression of key enterocyte-associated nutrient transporters. Focused experiments are needed to carefully identify the critical components of intestinal adaptation and yield conclusions regarding the relative contributions of SCFA and GLP-2 during the various phases of this process.

Fructans markedly shifted gut microbiota and improved intestinal physiology in obese mice, but the mechanisms by which they affect gut integrity and inflammation in the obese are still unknown.

No abstract

Chronic diseases develop in susceptible individuals following exposure to environmental conditions including high fat diets. Inbred strains of mice differing in susceptibility to atherosclerosis, diabetes, obesity and certain cancers are models for understanding the genetic basis and molecular mechanisms whereby diet influences these polygenic and multifactorial disorders. Expression sequence tags (EST) and disease quantitative trait loci (QTL) are also being identified with these strains. Reported here are comparisons of food intake, growth, nonfasting serum lipids and expression of mRNA for hepatic apolipoprotein E (ApoE), hepatic stearoyl CoA desaturase (Scd1) and heart lipoprotein lipase (Lpl) in a 2 x 2 x 2 design with C57BL/6J and BALB/cByJ mice fed semipurified diets with 4 or 20% saturated (coconut) or unsaturated (corn) oils for 4 mo. Histological studies of aortas and coronary arteries are also reported for these animals. After 4 mo, BALB/cByJ mice were significantly heavier and had significantly higher total serum cholesterol, HDL cholesterol and triglyceride concentrations in the fed state than C57BL/6J mice. Efficiency of utilizing dietary energy did not differ consistently between strains. Oil level affected serum total cholesterol, triglycerides and HDL cholesterol, which were significantly greater in mice fed high fat diets. Lpl and ApoE mRNA expression levels were not significantly affected by mouse strain, oil source or oil level. Scd1 mRNA expression, however, was significantly higher in C57BL/6J than in BALB/cByJ mice and was lower in all mice fed 20% compared with those fed 4% fat diets. Genes regulated differently by diet among strains with distinct susceptibility to diet-influenced disease may be associated with molecular pathways contributing to incidence or severity.

Prebiotics and dietary fibers are nondigestible ingredients that may confer benefits to the host by selectively stimulating beneficial intestinal bacteria and microbial-derived metabolites that support gut and host health. This experiment evaluated the effects of a blend of prebiotics and dietary fibers on apparent total tract digestibility (ATTD) and fecal metabolites related to gastrointestinal health in adult dogs. Four diets containing either 5% cellulose (control; CT), 5% dietary fiber and prebiotic blend (FP), 0.02% saccharin and eugenol (SE), or 5% fiber blend plus 0.02% saccharin and eugenol (FSE) were formulated to meet or exceed the AAFCO (2017) nutritional requirements for adult dogs. Eight adult female beagles (mean age 4.2 ± 1.1 yr; mean BW = 10.8 ± 1.4 kg; mean BCS = 5.8 ± 0.6) were randomly assigned to 1 of the 4 dietary treatments using a replicated 4 × 4 Latin square design. Each experimental period consisted of 14 d (10 d of diet adaptation and 4 d of total and fresh fecal and total urine collection). All animals remained healthy throughout the study, with serum metabolites being within reference ranges for adult dogs. All diets were well accepted by the dogs, resulting in similar (P > 0.05) daily food intakes among treatments. Likewise, fecal output and scores did not differ (P > 0.05) among dietary treatments, with the latter being within the ideal range (2.5–2.9) in a 5-point scale. All diets were highly digestible and had similar (P > 0.05) ATTD of dry matter (81.6%–84.4%), organic matter (86.4%–87.3%), and crude protein (86.6%–87.3%). However, total dietary fiber (TDF) digestibility was greater for dogs fed the FSE diet (P < 0.05) in contrast with dogs fed the CT and SE diets, whereas dogs fed FP diets had intermediate TDF digestibility, but not different from all other treatments. Fecal acetate and propionate concentrations were greater (P < 0.05) for dogs fed FP and FSE diets. Fecal concentrations of isobutyrate and isovalerate were greater for dogs fed CT (P < 0.05) compared with dogs fed the other three treatments. No shifts in fecal microbial richness and diversity were observed among dietary treatments. Overall, the data suggest that dietary supplementation of fiber and prebiotic blend was well tolerated by dogs, did not cause detrimental effects on fecal quality or nutrient digestibility, and resulted in beneficial shifts in fecal metabolites that may support gut health.

Dietary fibers have gained renewed interest in companion animal nutrition as a means to manage pet obesity and improve gut and host health. Soybean hulls (SBH), a coproduct of the soybean oil extraction process, is an accessible and economical fiber source. However, limited research is available on the use of SBH in feline nutrition. Thus, the aim of this study was to determine the effects of a high SBH inclusion level on daily food intake, apparent total tract (ATT) macronutrient digestibility, fecal quality, and fecal fermentative end products in diets of adult cats. Four diets were formulated with either SBH, beet pulp (BP), or cellulose (CL) as the main source of dietary fiber, with the control diet formulated with no added fiber (NF). The fiber treatments were formulated to achieve approximately 15% total dietary fiber (TDF). Eight adult male cats (mean age = 10.5 yr ± 0.1; mean BW = 6.1 ± 0.8 kg) were used in a replicated 4 × 4 Latin square design. Each period consisted of 14 d, with 10 d of diet adaptation followed by 4 d of total fecal and urine collections. Food was offered twice daily and cats were fed to maintain BW. Food intake on a DM basis (DMB) was lower (P < 0.05) in cats fed BP (55.2 g/d) when compared with SBH (70.8 g/d). As-is fecal output did not differ in cats fed BP or SBH, and when expressed on a DMB, fecal output did not differ among fiber treatments. The ATT digestibility of DM, OM, and GE was greater (P < 0.05) in cats fed NF when compared with those fed BP, CL, or SBH. Cats fed CL had the greatest (P < 0.05) ATT CP digestibility (88.5%), followed by cats fed NF (84.9) and SBH (81.7%) with the lowest values (77%) noted for cats fed BP. Acid-hydrolyzed fat (AHF) digestibility was greater for cats fed CL (92.9%) than for cats fed BP (86.9%) and SBH (88.6%). The TDF ATT digestibility was lowest for cats fed NF and CL (8.5% and 15.1%, respectively), followed by SBH (18.0%), with BP having the highest digestibility (33.7%). Total short-chain fatty acid concentration was greatest (P < 0.05) in cats fed BP (699.7 μmole/g) when compared with the other 3 treatments, whereas phenol and indole concentrations did not differ among treatments. In conclusion, a high inclusion level (15% TDF) of SBH appears acceptable in diets for adult cats, resulting in no negative effects on daily food intake, fecal scores, and similar ATT digestibility for most macronutrients when compared with BP and CL.