GSE210823
RNA-Seq Exploration of the Influence of Stress on Meat Quality in Spanish Goats
Studies exploring the transcriptome of stress and its effects on meat quality are very limited, particularly in goats.  Fifty-four male Spanish goats (8-mo old; BW = 29.7 ± 2.03 kg) were randomly subjected to one of three treatments (TRT; n = 18 goats / treatment): (i) transported for 180 min, (ii) transported for 30 min, or (iii) held in pens (control) to analyze the transcriptome of stress and meat quality in goats using RNA-seq technology. Blood samples were collected before and after treatment, and meat samples were collected after humane slaughter for stress hormone, meat quality (Longissimus dorsi), and transcriptomic analysis. Plasma epinephrine concentrations were higher (P < 0.01) in 180 min and 30 min groups compared to the control group; however, norepinephrine concentrations were not affected by the treatment. Muscle glycogen concentrations (15 min postmortem) were lower (P < 0.01) in both 30 min and 180 min groups compared to the control group. Calpastatin levels were higher (P < 0.01) in 180 min and 30 min groups than the control group. Warner-Bratzler shear force values of loin chops were the highest in the 180 min group (4 ± 0.15, kg), lowest in the control group (3.51 ± 0.10, kg), and intermediate in the 30 min group (3.78 ± 0.09, kg; P < 0.01) both at day 1 and day 6 aging time.  Additionally, desmin levels of day 6 samples were lowest in the control group, highest in 180 min group, and intermediate in 30 min group (P < 0.05).  RNA-seq results showed that a total of 10,633 genes were differentially expressed (5,194 up regulated; 5,439 down regulated) among all comparisons (blood and day 1 and day 6 muscle samples). Among these differentially expressed genes (DEGs), KLF9, AMPK, FOXO3, PTX3, GADD45, PTPN1, CASP7, MAPK4, HSPA12A, and JAK-STAT were probably associated with the effects of stress on skeletal muscle proteins and involved in biological process such as cellular response to corticosteroid stimulus, endoplasmic reticulum stress, insulin resistance, DNA repair, apoptosis, MAPK cascade and regulation of proteolysis.  The KEGG analysis revealed that AMPK and JAK-SAT signaling pathways and autophagy were among the top 20 enriched pathways in our treatment comparisons. The results provide an understanding of the genes and pathways involved in stress responses and related changes in postmortem muscle metabolism and meat quality characteristics in goats. Overall design: Prior to beginning of the experiment, the protocols for this research were duly reviewed and approved by the Animal Care and Use Committee at Fort Valley State University.  Fifty-four intact male Spanish goats (8-mo old; BW = 29.7 ± 2.03 kg), raised primarily on free range pasture with a grain supplement and with ad libitum access to hay and water, were used in this experiment.  The animals were randomly subjected to one of three stress treatments (TRT; n = 18 goats/treatment): (i) transported for 30 min (approx. 50 km), (ii) transported for 180 min (approx. 200 km), or (iii) held in pens (control), on two different days. A livestock trailer was used to transport the goats and the ambient temperatures were -3.0 ± 1.0 ºC and 1.0 ± 1.0 ºC on day 1 and 2, respectively. Feed was withheld overnight prior to the day of the experiment. Goats were slaughtered using humane procedures.