Evaluation of growth, deposition of back fat, and loin muscle for purebred Berkshire pigs housed in bedded hoop buildings.

This study was conducted to evaluate the accretion of BW, back fat, and loin muscle from purebred Berkshire pigs raised in bedded hoop barns in Iowa. The growth of a total of 144 purebred Berkshire pigs (18 barrows and 18 gilts per trial) was evaluated from 4 trials (2 winter and 2 summer trials). Pigs were fed ad libitum utilizing a 5-phase standard corn-soybean meal feeding program that met or exceeded NRC nutrient requirements. Pigs were housed in bedded hoop barns (unheated) to approximate common niche market requirements. At 21-d intervals, pigs were serially weighed, and ultrasonic back fat depth and loin muscle area (LMA) measurements were taken. Live BW measurements began at the trial initiation at approximately 18 to 32 kg, but ultrasonic scans for 10th-rib back fat depth and LMA began at between 36 and 45 kg until market weight of about 122 ± 2.5 kg. The rate (µ) of live body growth (weight) and ultrasonic back fat depth were influenced ( < 0.01) by trial and sex, with no significant interactions between trial and sex. Both live BW and back fat deposition were significantly greater in trial 1 than all other trials (2, 3, and 4). The rate of accretion and maximum growth of LMA depth were not affected ( > 0.05) by trial and sex. Overall, barrows averaged 31 mm of back fat at 125 kg, whereas gilts had an average of about 23 mm at 121 kg of market weight. Results suggest that because of the sex differences in growth and back fat deposition between Berkshire barrows and gilts, it may be important to formulate their diets differently in commercial pork production systems.

Gold nanoparticle-mediated gene delivery induces widespread changes in the expression of innate immunity genes.

The unique properties of oligonucleotide (and small interfering RNA)-modified gold nanoparticle conjugates make them promising intracellular gene regulation agents. We found that gold nanoparticles stably functionalized with covalently attached oligonucleotides activate immune-related genes and pathways in human peripheral blood mononuclear cells, but not an immortalized, lineage-restricted cell line. These findings have strong implications for the application of oligonucleotide-modified gold nanoparticle conjugates in translational research and in the development of therapeutics and gene delivery systems.

Prediction of fat-free mass of pigs from 50 to 130 kilograms live weight.

Seventy-two Duroc x Hampshire x Yorkshire pigs were used to evaluate bioelectrical impedance procedures to predict fat-free mass of live pigs. Pigs were allotted by sex, ancestry, and weight. Pigs (12 gilts and 12 barrows) averaging 50+/-2.4 kg were slaughtered to establish a baseline for body composition. A pen of six gilts and a pen of six barrows were randomly selected for slaughter when the pen averaged either 70, 90, 110, or 130 kg. Pigs were weighed, then a four-terminal plethysmograph was used to measure resistance (omega) and reactance (omega), and length (cm) was measured between detector terminals. Pigs were slaughtered 12 h later, and carcasses were chilled for 24 h. The right side was ground twice and mixed and samples were frozen for later analyses of fat content. Actual fat-free mass (ActFFM) was determined from the weights and percentage of fat. Predicted fat-free mass (PredFFM) was calculated using the following equation: Pred FFM = .486 (live weight) - .881 (resistance) + .48 (length) + .86 (reactance) + 7.959. The correlation coefficients between ActFFM and PredFFM ranged from .66 to .91 overall. Correlation coefficients approximating slaughter weight (90 kg) were .94 (P < .02). Fat-free mass was underestimated by the prediction equation at all slaughter weights, but the predicted fat-free mass was highly correlated to the actual fat-free mass, except for the 110-kg gilts (r = .68, P = .15) and the 130-kg barrows (r = .65, P = .16). The data support the use of bioelectrical impedance to measure fat-free mass over a wide range of weights for finishing pigs.

Bioelectrical impedance: a nondestructive method to determine fat-free mass of live market swine and pork carcasses.

Ninety-two swine averaging 104 +/- 4.5 kg and 99 cold carcasses averaging 75 +/- 3.1 kg were measured with a four-terminal plethysmograph. Pigs were transported to the abattoir, fasted 4 h, weighted, and measured for body resistance (Rs, omega), body reactance (Xc, omega), and distance (L, cm) between detector terminals that were located along the dorsal axis of the animal. Pigs were slaughtered 12 h later, carcasses were chilled for 24 h, then weighted (whole carcasses and side carcasses), and cold carcass Rs, Xc, and L measurements were obtained. The right side of the carcass was ground twice, and a 1-kg sample was frozen for later analyses of fat, ash, N, and moisture. Fat-free mass (FFM, kg) was calculated from weight and percentage of fat. Regression analyses were used to develop equations for estimating FFM on a live, adjusted live, whole carcass, and half-carcass basis. Live BW, Rs, and L accounted for the majority of the variation in FFM. Adjusting live BW for head, viscera, and blood weight increased the explained variation for live BW and decreased the variation accounted by Rs. Multiple regression models involving Rs, L, Xc, and weight accounted for 82, 84, and 84% of the variation for FFM expressed on a live, adjusted live, and cold carcass basis, respectively. Results from this study indicate that bioelectrical impedance has excellent potential as a rapid, nondestructive method for estimation of FFM for market swine and pork carcasses.