Housekeeping Proteins in Meat Quality Research: Are They Reliable Markers for Internal Controls in Western Blot? - A Mini Review

Advancements in technology and analytical methods enable researchers to explore the biochemical events that cause variation in meat quality. Among those, western blot techniques have been successfully used in identifying and quantifying the key proteins that have critical functions in the development of meat quality. Housekeeping proteins, like β-Actin, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and tubulins are often used as internal controls in western blots to normalize the abundance of the protein of interest. However, there are increasing concerns about using housekeeping proteins for western blot normalization, as these proteins do not demonstrate any loading differences above the relatively small total protein loading amounts of 10 μg. In addition, the interaction between these housekeeping proteins and the programmed cell death processes highlights the concerns about using the housekeeping protein as the internal control in meat quality research. Moreover, recent proteomic research has indicated that the abundance of some housekeeping proteins, like β-actin, GAPDH, and tubulin, can be altered by preslaughter stress, dietary supplementation, gender, slaughter method, genotype, breed, aging period, muscle type, and muscle portion. Furthermore, these housekeeping proteins could have differential expression in meat with differing color stability, tenderness, and water holding capacity. Therefore, this review aims to examine the realities of using housekeeping proteins as the loading control in meat quality research and introduce some alternative methods that can be used for western blot normalization.  

Analysis of Volatile Compounds in Sea Bass (Lateolabrax japonicus) Resulting from Different Slaughter Methods Using Electronic-Nose (E-Nose) and Gas Chromatography-Ion Mobility Spectrometry

Sea bass (Lateolabrax japonicus) is known for its unique flavor and high nutritional value. In this study, the influence of slaughter methods on the volatile compounds (VOCs) in sea bass was investigated using electronic nose (E-nose) technology and gas chromatography-ion mobility spectrometry (GC-IMS). VOCs in raw and cooked sea bass resulting from different slaughter methods were effectively distinguished using both techniques. Aldehydes, ketones, and alcohols were associated with the basic flavor of sea bass, whereas esters, organic acids, and furans enriched the aroma. In raw sea bass, the fishy odor was the strongest in the HSD group (head shot control death), followed by that in the IFD (ice faint to death) and BDS (bloodletting to death) groups. The VOC content increased and stabilized after steaming, enhancing pleasant odors such as fatty and fruity aromas. In cooked sea bass, the content of diacetyl and ethanol was the highest in the EAD group (eugenol anesthesia to death), which may be a residue of eugenol, imparting a distinct irritating chemical odor. Furthermore, abundant (E)-2-octenal, 2-heptanone, benzaldehyde, and esters in the BDS group imparted a strong, pleasant aroma. The findings indicate that heart puncture and bloodletting is the preferred slaughter method to maintain sea bass quality, providing new insights into the volatile changes in sea bass induced by different slaughter methods.

Conventional versus Ritual Slaughter–Ethical Aspects and Meat Quality

Social pressure on increased protection and welfare of animals results mainly from the initiative of people living in the urbanized parts of the world. The respect for the right to freedom of religion, which is indisputably one of the fundamental liberal rights, must be taken into account. The right to freedom to religion also includes the right to follow a religion’s dietary recommendations. The aim of the literature analysis was to systematize the knowledge on the ethical aspects and quality of meat obtained from carcasses of animals subjected to conventional and ritual slaughter. Consistent with the importance of ritual slaughter for humans of two major faiths (Islam and Judaism), it is important that scientists be objective when evaluating these practices from an animal welfare and meat quality point of view. To evaluate the welfare of the slaughtered animal, it is necessary to openly discuss ritual slaughter and the improvement of its methods. The quality of meat and the degree of bleeding of animals do not always correlate with the ritual slaughter method used.

Indigenous Slaughter Techniques: Effects on Meat Physico-Chemical Characteristics of Nguni Goats

To improve goat meat quality in rural communities, it is important to evaluate the effects of indigenous slaughter methods used by resource-limited farmers when performing traditional ceremonies on the meat physico-chemical characteristics. The current study assessed the effects of the meat physico-chemical characteristics of Nguni goats slaughtered with the transverse neck incision (TNI), suprasternal notch piercing (SNP) and the under shoulder blade piercing at the chest floor point of elbow (CFP) to the direction of the heart methods. Thirty Nguni weathers were randomly assigned to three slaughter treatments (10 goats/treatment). Musculus longissimus thoracis et lumborum (LTL) was sampled at post-mortem for physico-chemical characteristic measurements. Meat from wethers slaughtered with the SNP method had greater ultimate pH values than meat from wethers slaughtered with TNI and CFP slaughter methods. Wethers slaughtered with the SNP method had lower meat redness (a*), yellowness (b*), and chroma (C*) values than those slaughtered with TNI and CFP slaughter methods. Goat slaughter method did not affect meat drip loss, water holding capacity, cooking loss and shear force. Overall, Nguni wethers slaughtered with the TNI and CFP methods produced chevon with fresher meat appearance than those slaughtered using the SNP method.

Performance, body composition and net requirements of protein and energy for weight gain in steers supplemented with or without addition of lipids

This research aimed to evaluate the performance, body composition and net requirements for protein and energy in grazing Nellore steers supplemented with or without addition of lipids. Twenty-eight steers, 301 ± 5.8 kg BW, were used in the experiment. The comparative slaughter method was used, with four steers used as references. The remaining 24 steers were randomly distributed into four groups, during 180 days, according to treatment: only Panicum maximum cv. Mombasa grass; Mombasa grass with concentrated supplementation based on soybean meal; Mombasa grass with concentrate containing lipids from soybean oil; and Mombasa grass with concentrate containing lipids derived from soybean grains. The total DMI of the steers fed only the pasture did not differ (P > 0.05) from the average intake of the treatments with or without addition of lipids. There were no differences (P > 0.05) between treatments for total daily gain, carcass and non carcass for protein, energy and fat. The requirements of protein and energy did not differ (P > 0.05) among the treatments. When the pasture is of good quality, supplementation does not alter the body composition or the net requirements of protein and energy for weight gain. The supplementations with higher concentrations of lipids (oil and grain) were not enough to promote greater gains in fat and energy in carcass.

Effect of Indigenous Slaughter Methods on the Behavioural Response, Bleeding Efficiency and Cardiac Arrest of Nguni Goats

Resource-limited farmers slaughter goats without stunning. The objective of the current study was to assess the influence of indigenous slaughter methods used by resource-limited households on slaughter stress-related behaviour, bleeding efficiency, and time to post-slaughter trauma of goats. Thirty clinically healthy castrated Nguni goats aged between 15 to 18 months old with body condition score of three were randomly assigned to three non-stunning informal slaughter methods, (1) transverse neck incision (TNI); (2) suprasternal notch piercing in the direction of the heart (SNP); and (3) under-shoulder-blade chest-floor point-of-elbow (CFP) sticking in the direction of the heart. Ten goats were slaughtered using each method. Slaughter method had no effect (p < 0.05) on stress-related behaviour. Rate of bleeding efficiency was highest (p < 0.05) for SNP slaughtered goats. Time to lose sensibility was lowest (p < 0.05) for goats slaughtered using the CFP (55 s) when compared to SNP (68 s) and TNI (75 s) slaughter methods. Time to post-slaughter trauma was highest (p < 0.05) for SNP (247 s) and lowest for TNI (195 s). These findings suggest that goats slaughtered with SNP experienced rapid death when compared to TNI and SNP slaughter methods. It was concluded that the SNP slaughter method is the most effective slaughter technique because it is associated with higher bleeding efficiency and lower time to lose sensibility before death.

PSXIII-26 Are consumers’ culinary skills related to their purchasing attitudes towards pork?

Consumers’ food-related lifestyles may affect purchasing attitudes towards meat. This study aimed to evaluate the impact of consumers’ culinary skills on their attitudes towards pork in two country regions of North-Eastern Spain and Portugal. Survey data were collected through an on-line questionnaire (Catalonia, n = 442; Aragon, n = 342; Northern Portugal, n = 190; all of whom consumed pork). Each respondent was asked questions regarding consumer purchasing habits that were used to segment the consumers through hierarchical clustering according to their culinary skills. A 5-point Likert scale was used to assess the importance of intrinsic and extrinsic cues towards pork (20 questions). Wilcoxon tests with pair-wise comparisons were conducted to cross consumer clusters with their purchasing drivers. Two optimal clusters were identified: “uninvolved” consumers that liked cooking to a lesser extent (P &lt; 0.001), normally ate out on working days (P &lt; 0.001), considered traditional recipes best (P = 0.008), spent less time cooking (P &lt; 0.001), did not like changes in their meals (P &lt; 0.001), considered less important meal planning for family nutrition (P &lt; 0.001), enjoyed to a lesser extent shopping for food (P &lt; 0.001), payed less attention to advertisements (P = 0.03) and food label information (P &lt; 0.001) than “innovative cook lovers.” Interestingly, the two clusters did not differ in enjoying social eating out, following a shopping list, preferring butchers rather than supermarkets, or over the counter purchases rather than packaged meat. “Best before date,” “safety” and “appeal (colour, drip loss)” were the most important criteria for purchase decision in both clusters. The “price” importance was greater (P &lt; 0.05) whereas “cooking ease” was less valued (P = 0.04) by “innovative cook lovers” than by “uninvolved” consumers. The least rated driver was “slaughter method,” although it was scored greater by “innovative cook lovers” than by “uninvolved” consumers (P = 0.04). In summary, innovative cook lovers may be more exigent consumers (price and animal welfare sensitive).

Influence of selected factors on meat quality from farm-raised and wild fallow deer (Dama dama): a review

Fallow deer meat (venison) is a new product acquired from farm-raised and wild animals. Nowadays, people are more concerned about their health, and therefore, they search for high quality, “healthy” products. Farming of fallow deer is ecological and friendly to the environment. Animals are kept in pasture conditions which resemble their natural environment. Venison is considered healthy meat, low in fat and cholesterol, and high in protein. The aim of this review was to gather and discuss the available literature on factors influencing the quality of venison such as sex, age, slaughter method and housing system, feeding, hanging method, animal condition, muscle type, and ageing of meat, considering both farm-raised and wild fallow deer.