Broiler stunning is conducted to produce a rapid onset of insensibility prior to slaughter. Though most broiler plants use electrical stunning applications, gas stunning, and low-atmosphere pressure stunning are also available for commercial applications. All three of these stunning methods are able to meet animal welfare requirements and produce meat with acceptable quality. However, each method differs in their mechanisms of stunning, rigor mortis patterns, and physical meat characteristics. In addition, gas stunning and low-atmosphere pressure stunning have received interest over the past decade as part of an effort to further improve animal welfare. Researchers have reported that gas and low-atmosphere pressure stunning both have potential advantages over electrical stunning with respect to broiler welfare and deboning time, which has been attributed to shackling post-stunning. This review paper will focus on these three stunning methods and their impact on animal welfare, physiology, rigor mortis patterns, carcass characteristics, and meat quality.

A completely randomized design with 7 replications (n = 7, treatments = 5 with 8 subsamples per treatment) was used to evaluate the effects of feeding various levels of distillers dried grains with solubles (DDGS; 0, 6, 12, 18, and 24%) on broiler breast and thigh meat quality. Broilers were harvested in a pilot scale processing plant with commercial prototype equipment at 42 d of age. The right half of each breast was evaluated for pH, instrumental color, cooking loss, proximate analysis, and tenderness. The left half of each breast was used for consumer acceptability testing. Thigh meat was evaluated for proximate composition, fatty acid composition, and TBA reactive substances. Breast meat from broilers that were fed DDGS had a higher (P < 0.05) pH than those from the control diet. In addition, the 18 and 24% DDGS treatments yielded breast meat with higher (P < 0.05) pH values than the 6% DDGS treatment. No differences existed (P > 0.05) among breast meat from the different treatments with respect to cooking loss, instrumental color, and consumer acceptability, but breast meat from the control (0% DDGS) treatment had slightly lower (P < 0.05) shear force than breast meat from the 18 and 24% DDGS treatments. In addition, no differences (P > 0.05) existed among proximate composition of breast and thigh meat from the control and DDGS treatments. As DDGS concentration increased, there was a linear increase (P < 0.05) in linoleic and polyunsaturated fatty acids, which indicates a greater potential for lipid oxidation. The TBA reactive substances values were greater (P < 0.05) for the 18 and 24% DDGS treatments at d 5 when compared with the control and 6% DDGS treatments, which indicates increased oxidation. Overall, data suggest that all treatments yielded high-quality breast meat and that thigh meat quality was similar among treatments containing 0 to 12% DDGS, but higher inclusion levels led to thigh meat that was more susceptible to oxidation.

Significant errors were found in a paragraph on page 758. The paragraph should be rewritten as “Because linoleic acid concentrations increased in thigh meat as concentration of DDGS increased in the broilers diets (Table 4), there may be potential health benefits to feeding DDGS to broilers. Linoleic acid is a n-6 essential fatty acid that is generally considered healthier than saturated fatty acids that were decreased as DDGS feed concentration increased. However, because most Western diets have an excess of linoleic acid in comparison to n-3 fatty acids such as linolenic acid (McClements and Decker, 2008), it is not clear whether there would truly be an enhanced health benefit from feeding DDGS.” In addition, 3 fatty acids should have been written differently in Table 4. Fatty acids were listed based on the first fatty acid closest to the glycerol backbone and should have been listed based on whether they were n-3 or n-6 fatty acids. The corrected table is listed below. The authors regret these errors.

Consumer research was conducted to evaluate the acceptability of choice and select steaks from the Longissimus lumborum that were cooked to varying degrees of doneness using demographic information, cluster analysis and descriptive analysis. On average, using data from approximately 155 panelists, no differences (P>0.05) existed in consumer acceptability among select and choice steaks, and all treatment means ranged between like slightly and like moderately (6–7) on the hedonic scale. Individual consumers were highly variable in their perception of acceptability and consumers were grouped into clusters (eight for select and seven for choice) based on their preference and liking of steaks. The largest consumer groups liked steaks from all treatments, but other groups preferred (P<0.05) steaks that were cooked to various end-point temperatures. Results revealed that consumers could be grouped together according to preference, liking and descriptive sensory attributes, (juiciness, tenderness, bloody, metallic, and roasted) to further understand consumer perception of steaks that were cooked to different end-point temperatures.

A randomized complete block design with 3 replications (n = 432, 72 broilers per treatment) was used to evaluate the effects of electrical (ES) and vacuum stunning (VS) on broiler breast meat quality. Electrical stunning was performed by applying 11.5 V, <0.05 mA, AC to DC current for 3 s for each broiler. Vacuum stunning was accomplished by exposing the birds to a low atmospheric pressure of 597 to 632 mmHg in an airtight decompression chamber. Breast removal was then performed at 0.75, 2, and 4 h postmortem for each stunning method. Color, pH, cook loss, and shear force values were measured on breasts that were removed from the right side of the carcass. Breasts removed from the left side of the carcass were used for consumer acceptability testing. The L* values were lower (P < 0.05) for VS than ES at 4-and 2-h deboning times. On average, 15-min and 24-h postmortem pH values were not different (P > 0.05) for both stunning method and deboning time. Shear force did not differ (P > 0.05) between stunning methods but decreased (P < 0.05) as deboning time increased. On average, no differences (P > 0.05) existed in consumer acceptability (appearance, texture, flavor, overall) among breast meat from ES or VS birds that were deboned at 2 or 4 h. However, consumers could be clustered into 8 groups based on preference and liking of samples regarding overall and texture acceptability. Sixty-five percent of consumers (3 clusters) liked all broiler breast treatments. Within these 3 clusters, some consumers preferred (P < 0.05) 4-h deboned samples over those deboned at 2 h (cluster 7), and other consumers preferred (P < 0.05) those deboned at 2 h over 4-h samples (cluster 6). Data revealed that both stunning methods provided high-quality breast meat with minimal product differences.

The cardiac L-type voltage-dependent calcium channel (VDCC) is a critical component of cardiac action potential and excitation-contraction coupling. The objective of the present study was to examine the changes in expression in Motif IV, an alternatively spliced region of the α-1 subunit of the VDCC channel in post-myocardial infarction (MI) remodeled rat left ventricle. RNase protection assay was used to determine alteration in isoform expression in the noninfarcted hypertrophied ventricular myocardium 21 days post myocardial infarction. Our study demonstrates that cardiac hypertrophy is associated with significant increase in the mRNA level of the fetal isoform, with the reversion of fetal:adult isoform ratio to the fetal phenotype. Changes in isoform expression in the post-MI remodeled ventricle, not previously reported, is a pertinent genetic marker of cardiac hypertrophy.