Prediction of carcass composition and individual carcass cuts of Japanese Black steers.

The objective of this study was to develop equations to predict carcass tissue weights and percentages and boneless carcass non-trimmed cut weights by using the cold carcass weight (CCW) and three other traits at the 6-7th rib section, which are routinely collected in carcass markets in Japan. Carcasses from 94 Japanese Black steers were used for the multiple regression analysis with a stepwise procedure and a novel Least Absolute Shrinkage and Selection Operator (LASSO). The accuracies of prediction (R(2)) and RMSEs for the carcass tissue and cut weights were similar between the two procedures. In contrast, LASSO appeared to be the better procedure for predicting carcass tissue percentages. The longissimus muscle area and subcutaneous fat thickness were the important predictors for the lean percentage in the stepwise procedure, and CCW was additionally selected when the LASSO procedure was used.

Molecular cloning and characterization of porcine Mx2 gene.

Mx, an interferon-inducible protein, is found in various vertebrates and confers resistance to several RNA viruses. At least two Mx proteins occur in vertebrates, and these proteins are key components of innate defense against viral infection. In mice and humans, the two Mx genes have different antiviral activities. Both Mx1 and Mx2 have also been detected in pigs, although only a partial sequence of porcine Mx2 has been reported, and there is no information on its antiviral activity. Here, we report the structure of the intact porcine Mx2 gene having an open reading frame of 2136 bp. We also determined the sequence of the genomic region containing the entire porcine Mx2 gene in addition to Mx1 gene. A weak constitutive expression of porcine Mx2 mRNA and endogenous Mx2 protein was observed in interferon-untreated cells. Porcine endogenous Mx2 protein showed nuclear localization. Furthermore, assays using NIH3T3 cells transfected with Mx genes showed that porcine Mx2 possessed antiviral activity against influenza, although this activity was lower than that of human MxA. This report is the first to describe the intact porcine Mx2 gene, which is a functional gene that may play a key role in the clearance of viruses in pigs.

A naturally occurring variant of porcine Mx1 associated with increased susceptibility to influenza virus in vitro.

Mx1 has been implicated in resistance to the influenza virus. We have now identified four alleles of the Mxl gene in domesticated breeds of pigs. Two of the alleles encode deletion variants (a 3-bp deletion in exon 13 and an 11-bp deletion in exon 14), which might be expected to interfere with Mx activity. The porcine Mxl genes corresponding to wild type, the 3-bp deletion mutant, and the 11-bp deletion mutant were cloned and expressed in NIH3T3 cells, and the antiviral activity for influenza virus was assayed. Virus yield was observed to be 10-100-fold greater with the 11-bp deletion allele than that for wild type and the 3-bp deletion alleles. The results suggest that the 11-bp deletion type is lacking antiviral activity able to contribute to the interference of influenza virus replication.

PCR detection of DNAs of animal origin in feed by primers based on sequences of short and long interspersed repetitive elements.

PCR primers for the detection of materials derived from ruminants, pigs, and chickens were newly designed on the basis of sequences of the Art2 short interspersed repetitive element (SINE), PRE-1 SINE, and CR1 long interspersed repetitive element (LINE), respectively. These primers amplified the SINE or LINE from total DNA extracted from the target animals and from test feed containing commercial meat and bone meal (MBM). With the primers, detection of Art2, PRE-1, or CR1 in test feed at concentrations of 0.01% MBM or less was possible. This method was suitable for the detection of microcontamination of feed by animal materials.