Evaluation of a rendered poultry mortality-soybean meal product as a supplemental protein source for pig diets.

Dehydrated/rendered broiler mortality-soybean meal products (DPS) were evaluated in two trials as high-protein feedstuffs for pig diets. Broiler mortalities, collected and frozen on-farm and transported to a central facility, were minced, blended with soybean meal, and dried with a final product temperature of 120 to 130 degrees C. The final DPS products used contained approximately 30 and 45% (DM basis) dried broiler mortality for the first and second trials, respectively (DPS1 and DPS2). The first trial involved 50 young, growing pigs (9 to 26 kg) and the second, 72 growing and finishing pigs (27 to 111 kg). The trials compared corn-based diets containing either soybean meal (SBM; 48%) or DPS products as the supplemental protein source. The DPS products averaged 50% CP and 2.9% total lysine; crude fat content of DPS used in the first trial was 8%, and for the second, 14.6% (as-fed basis). The ADG of pigs fed the DPS diets in either trial was similar to that of pigs fed the SBM control diets. In the second trial, pigs fed DPS2 had an overall average G:F ratio that was 9% better (P < 0.01) than that of pigs fed the SBM control diets. Carcass characteristics and pork quality from pigs of the growing-finishing trial were not affected by dietary treatment. Subjective carcass fat firmness scores indicated slightly softer fat (P < 0.05) from pigs fed DPS2. The mincing, blending with SBM, and dehydration of frozen stored on-farm broiler mortalities produced a safe and nutritious protein feedstuff for pigs, while also offering a viable disposal option.

In yeast, upc2-1 confers a decrease in tolerance to LiCl and NaCl, which can be suppressed by the P-type ATPase encoded by ENA2.

Wild-type yeast cells are unable to take up sterols from their growth media under aerobic conditions and are relatively resistant to monovalent cations. A yeast mutant (upc2-1) with a defect in the aerobic exclusion of sterols was found to have increased sensitivity to LiCl and NaCl. Although cation sensitivity has been reported for mutants that synthesize altered sterols, the mutant with upc2-1 continues to produce the normal sterol, ergosterol. The ENA2 gene was cloned on the basis of remediating the hypersensitivity to the monovalent cations.

A mutation in a purported regulatory gene affects control of sterol uptake in Saccharomyces cerevisiae.

Aerobically growing wild-type strains of Saccharomyces cerevisiae are unable to take exogenously supplied sterols from media. This aerobic sterol exclusion is vitiated under anaerobic conditions, in heme-deficient strains, and under some conditions of impaired sterol synthesis. Mutants which can take up sterols aerobically in heme-competent cells have been selected. One of these mutations, designated upc2-1, gives a pleiotropic phenotype in characteristics as diverse as aerobic accumulation of sterols, total lipid storage, sensitivity to metabolic inhibitors, response to altered sterol structures, and cation requirements. During experiments designed to ascertain the effects of various cations on yeast with sterol alterations, it was observed that upc2-1 was hypersensitive to Ca2+. Using resistance to Ca2+ as a screening vehicle, we cloned UPC2 and showed that it is YDR213W, an open reading frame on chromosome IV. This belongs to a fungal regulatory family containing the Zn(II)2Cys6 binuclear cluster DNA binding domain. The single guanine-to-adenine transition in upc2-1 gives a predicted amino acid change from glycine to aspartic acid. The regulatory defect explains the semidominance and pleiotropic effects of upc2-1.

Determination of sensory, chemical and cooking characteristics of retail beef cuts differing in intramuscular and external fat.

Top loin (TLS), top sirloin (TSS), and eye of round (EYS) steaks, and loin end (LRR) and blade end (BRR) rib, and eye of round (EYR) roasts were used to determine the effect of USDA quality grade, Choice or Select, external fat trim level, and internal temperature endpoint on sensory, chemical and cooking characteristics. Cuts cooked with external fat required slightly greater cooking times and had higher fat content in the lean than cuts cooked without external fat (p < 0.05). Regardless of quality grade or external fat trim, increasing internal temperature endpoint resulted in tougher, drier cuts with longer cooking times and greater cooking loss (p < 0.05). Choice TLS, TSS and LRR were higher (p < 0.05) in palatability than Select, but quality grade did not affect palatability of BRR, EYS or EYR.

Assessment of the essentiality of ERG genes late in ergosterol biosynthesis in Saccharomyces cerevisiae.

Isogenic strains of yeast were constructed, differing only in insertionally inactivated genes for ergosterol biosynthesis. These and their allelic wild-types were grown in competition to ascertain growth differences and any selective advantage for organisms producing sterols with or without specific features of ergosterol. In every instance tested, the wild-type allele afforded a competitive advantage over the isogenic pair producing modified sterol structures instead of ergosterol. A general trend was seen in which the earlier in the biosynthetic pathway that a mutation occurred, the less able the strain producing the defective sterols could compete with the ergosterol-producing strains.

Aerobic isolation of an ERG24 null mutant of Saccharomyces cerevisiae.

The ERG24 gene, encoding the C-14 sterol reductase, has been reported to be essential to the aerobic growth of Saccharomyces cerevisiae. We report here, however, that strains with null mutations in the ERG24 gene can grow on defined synthetic media in aerobic conditions. These sterol mutants produce ignosterol (ergosta-8,14-dienol) as the principal sterol, with no traces of ergosterol. In addition, we mapped the ERG24 gene to chromosome XIV between the MET2 and SEC2 genes. Our results indicate that ignosterol can be a suitable sterol for aerobic growth of S. cerevisiae on synthetic media and that inactivation of ERG24 is only conditionally lethal.