Obesity leads to changes in the gut microbial community which contribute to the metabolic dysregulation in obesity. Dietary fat and fiber affect the caloric density of foods. The impact of dietary fat content and fiber type on the microbial community in the hind gut is unknown. Effect of dietary fat level and fiber type on hindgut microbiota and volatile fatty acid (VFA) profiles was investigated. Expression of metabolic marker genes in the gut, adipose tissue and liver was determined. A 2×2 experiment was conducted in pigs fed at two dietary fat levels (5% or 17.5% swine grease) and two fiber types (4% inulin, fermentable fructo-oligosaccharide or 4% solka floc, non-fermentable cellulose). High fat diets (HFD) resulted in a higher (P<0.05) total body weight gain, feed efficiency and back fat accumulation than the low fat diet. Feeding of inulin, but not solka floc, attenuated (P<0.05) the HFD-induced higher body weight gain and fat mass accumulation. Inulin feeding tended to lead to higher total VFA production in the cecum and resulted in a higher (P<0.05) expression of acyl coA oxidase (ACO), a marker of peroxisomal β-oxidation. Inulin feeding also resulted in lower expression of sterol regulatory element binding protein 1c (SREBP-1c), a marker of lipid anabolism. Bacteria community structure characterized by DGGE analysis of PCR amplified 16S rRNA gene fragments showed that inulin feeding resulted in greater bacterial population richness than solka floc feeding. Cluster analysis of pairwise Dice similarity comparisons of the DGGE profiles showed grouping by fiber type but not the level of dietary fat. Canonical correspondence analysis (CCA) of PCR- DGGE profiles showed that inulin feeding negatively correlated with back fat thickness. This study suggests a strong interplay between dietary fat level and fiber type in determining susceptibility to obesity.

Globally, genetic diversity of livestock populations is contracting. Knowing the true extent of the contraction is needed to develop effective conservation strategies. Although contractions of genetic diversity have been documented at the breed level, little within breed documentation has occurred. This situation is no different for US swine breeds. Therefore, the objective of this study was to establish an inbreeding baseline for 5 pig breeds via pedigree records extracted from purebred registrations to each breed association for Berkshire (n = 116,758), Duroc (n = 878,480), Hampshire (n = 744,270), Landrace (n = 126,566), and Yorkshire (n = 727,268). For all breeds the number of registrations peaked after 1990 and declined since that time. The breeder structure was analyzed for Berkshire and Duroc; the average breeder registered pigs for 4.0 yr for both breeds. Breeders were grouped by longevity and herd size, and the inbreeding levels for the current population (pigs born 2006 and later) were evaluated. Presently, more than 99% of all pigs are inbred with the majority having inbreeding less than 10%. The range for percentage of animals that are more than 25% inbred ranged from 1.16% for Yorkshire to 6.09% for Berkshire. The greatest inbreeding for all animals within a breed ranged from 51% for Landrace and 65% for Yorkshire. Sires were grouped into 10 percentiles based on number of great-grandprogeny (GGP) produced; for all breeds, the top 10 percentile accounted for more than 75% of all GGP. Sixty percent of all sires produced less than 1% of all GGP, indicating few males are contributing to future generations. Generations ranged from 17 to 19 per breed with a generation interval ranging from 1.65 yr for Berkshire to 2.21 yr for Yorkshire. Mean inbreeding (%) at generation 17 (the most generations computed across breeds), rate of inbreeding per generation, and effective population size were 12.3, 0.0065, and 77 for Berkshire; 11.8, 0.0044, and 113 for Duroc; 6.8, 0.0046, and 109 for Hampshire; 17.9, 0.0067, and 74 for Landrace; and 8.0, 0.0044, and 113 for Yorkshire, respectively. The 2 breeds with fewest registrations, Berkshire and Landrace, had greater inbreeding rates and smaller effective population sizes, suggesting a need for more immediate conservation efforts. This analysis provides a basis for future monitoring of the genetic diversity of pig breeds and serves as a basis for planning conservation activities.

Mature Charolais x Angus cows (n = 128) were adjusted to a body condition score (BCS) of 3 (1 = very thin, 3 = moderate, 5 = very fat) between 130 and 190 d of gestation. When cows averaged 190 d of gestation, they were assigned randomly to a maintenance energy diet (ME) or to a diet very low in energy (LE). Cows were allotted within these prepartum (PRP) diets to a high-energy (HE) or LE diet at parturition. At 30 d postpartum (PP), cows were allotted to four treatments: a) slaughter at 0 (n = 32) or b) 48 h after calf removal (n = 32), c) cows whose calves were early weaned at 30 d PP (n = 32) or d) normally weaned at 205 d PP (n = 32). Low energy PRP intake reduced (P less than .01) BCS, cow weight, total empty body lipid (TEBL), body energy (BE) and daily predicted maintenance energy (PME)/W.75 by parturition. Pre- and postpartum energy intake combined to affect (P less than .10) these same factors in a similar manner at 30 d PP. From 30 to 60 d PP, early weaning reduced (P less than .05) PME/W.75. Cow BCS at 190 d of gestation had little effect (P greater than .10) on PME/W.75 or PME/Mcal of BE. Body condition score at parturition, however, affected (P less than .05) delta BCS, delta BE and PME/Mcal of BE by 30 and 60 d PP, with thinner cows losing less condition and requiring more PME/Mcal of BE. Cow BCS had a similar effect from 30 to 60 d PP. Total daily PME was greater for the fat cows during both the PRP and PP periods. Body composition, PRP and PP energy intake and early weaning affect energy requirements and energetic efficiency of beef cows.

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Pubertal characters of bulls and heifers produced in a diallel mating of Angus, Brahman, Hereford, Holstein and Jersey cattle were analyzed. Ninety-one heifers and 138 bulls in individual pens adn 286 bulls in drylots were fed a 72% TDN diet ad libitum; another 384 heifers were placed on pasture with supplemental feed. Puberty in heifers was defined as time of first ovulatory estrus; in bulls, as first detection of sperm cells in an electroejaculate. Breed type least-squares means, adjusted for birth month, were estimated within sex-nutrition-management groups and then decomposed into breed effects, average heterosis (h), general combining ability (GCA) and specific combining ability (SCA) by diallel analysis techniques. Breed effects were a significant source of variation for all characters studied. Heterosis (h, GCA, SCA) was not significant for pubertal age of bulls or heifers receiving complete diets in pens, a rather high nutritional plane. However, on pasture, crossbred heifers reached puberty at a younger age (P less than .05) than straightbreds. Average heterosis was significant (P less than .05) for increased weight and hip height at puberty and ratios involving these characters for both sexes. Specific combining abilities were not statistically significant for the majority of the pubertal characters, yet large differences among estimates of combining abilities were expressed. Ad libitum feeding of the penned heifers tended to decrease pubertal age and increase pubertal size as compared to pubertal age and size of pastured heifers. The breed type x management interactions within both sexes indicated a different ranking of the breed types for each management regimen.