Impacts of in utero heat stress on carcass and meat quality traits of market weight gilts

Authors: TUELL, JACOB - Purdue University; NONDORF, MARIAH - Purdue University; MASKAL, JACOB - Purdue University; Johnson, Jay; KIM, YUAN - Purdue University

Submitted to: Animals
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2021
Publication Date: 3/6/2021
Citation: Tuell, J.R., Nondorf, M.J., Maskal, J.M., Johnson, J.S., Kim, Y.H. 2021. Impacts of in utero heat stress on carcass and meat quality traits of market weight gilts. Animals. 11(3). https://doi.org/10.3390/ani11030717.
DOI: https://doi.org/10.3390/ani11030717

Interpretive Summary: Climate change threatens the efficiency and sustainability of pork production systems. Postnatal heat stress is well documented to adversely affect carcass and meat quality in swine. Exposure of the fetus to maternal hyperthermia, known as in utero heat stress, has also been demonstrated to influence postnatal performance traits of pigs, leading to dissimilar carcass composition when market weight is reached. The commonly observed differences in carcass composition of in utero heat stressed pigs include increased backfat thickness and fat accretion at the expense of lean mass, decreased loin muscle area, and lower head weight. However, the effects of in utero heat stress on carcass and meat quality attributes remain poorly understood. Therefore, this study evaluated the effects of exposure of the porcine fetus to in utero heat stress during the first half of gestation on carcass and meat quality attributes when market weight was reached. Pigs exposed to in utero heat stress had lower head and heart weights at slaughter compared to the thermoneutral group. Most measures of carcass quality were not impacted by the treatments, but lower loin muscle area was observed for in utero heat stress carcasses. Additionally, the loins from the in utero heat stressed pigs were found to be tougher, regardless of the duration of aging. Accordingly, minimizing heat stress experienced by pregnant pigs would be considered an important factor in improving both yield and quality of pork production systems.

Technical Abstract: This study evaluated the impacts of in utero heat stress (IUHS) on the carcass and meat quality traits of offspring when market weight was reached. Twenty-four F1 Landrace x Large White gilts were blocked by body weight and allocated among thermoneutral (IUTN) or IUHS treatments from d 6 to 59 of gestation. The offspring were raised under identical thermoneutral conditions, and gilts (n = 10/treatment) at market weight (117.3 ± 1.7 kg) were harvested. At 24 h postmortem, the loins (M. longissimus lumborum) were obtained, and sections were allocated among 1 d and 7 d aging treatments at 2 °C. Carcasses from IUHS pigs had lower head and heart weights (p < 0.05), as well as decreased loin muscle area (p < 0.05) compared to IUTN pigs. Instrumental tenderness was im-proved with aging regardless of in utero treatment (p < 0.05), although IUHS loins were tougher. Treatments had no other impacts on carcass and meat quality traits (p > 0.05), and western blots suggested increased toughness of IUHS loins was not due to proteolysis. These results suggest minimizing IUHS during the first half of gestation may be beneficial in improving pork yield and quality, though in general the effects of IUHS would be minimal.