Morphological and biochemical parameters of blood and quality of meat obtained from pigs with different stress resistance

Abstract

The results of the experiments were used to evaluate the morphological and protein composition of blood, as well as the quality of meat from pigs of different stress resistance. The studies were carried out under the conditions of PJSC ‘Stepovyi’ in Zaporizhzhia Region on Large White (LW) pigs and Large White/Charcoal Landrace (LWCL) crossbreeds. During the study period, the hygienic conditions of keeping, feeding and watering of the animals, their growth and development, clinical condition and morbidity were evaluated. After reaching a live weight of 100 kg, the pork meat quality (pH, moisture content, oxyproline, tryptophan) of slaughtered animals was studied. It was found that the LW genotypes were superior to the local LWCL by the number of leukocytes in passively resistant (PR) animals — by 2.7%, in stress resistant (SR) animals — by 3.15%, and in stress sensitive (SS) animals they were inferior by this indicator by 7.7%. There was no significant difference in erythrocyte content between SR and SS, but erythrocyte content was 8.53% lower in PR. The concentration of hemoglobin was higher in PR animals of the Large White cross. The latter were superior to LW in terms of total protein: PR — by 2.26%, SR — by 1.9%, in terms of albumin — PR had an advantage of 16.6%, SR — by 7.69% (p < 0.05). Gamma globulin content was 6.44% lower in SS animals. They were superior to LW in terms of live weight: PR — by 14% at one month of age; by 4.2% at four months of age, SR — by 6.2%, but the difference between SR and SS was not significant. PR animals of the Large White breed were superior in terms of hemoglobin content. The level of total protein in blood serum was higher in crossbred genotypes: in PR — by 2.26%, in SR — by 1.9%. The concentration of albumin was higher in the crossbred animals than in the LW: PR — by 16.6%, SR — by 7.69%, and the level of gamma globulins was 6.51% lower in the SS. In terms of live weight, crossbred genotypes outperformed LW: passive resistant genotypes — by 14% at one month of age, stress resistant genotypes — by 6.2% and 4.2% at four months of age. The crossbred genotypes reached 100 kg live weight: PR — at 180 days, SR — at 183 days, SS — at 191 days, which is 4, 5, and 12 days earlier than LW, respectively. In crossbred pigs, the positive correlation for thoracic girth was 0.6942 and 0.8310, and for withers height — 0.6643 and 0.6811. In terms of body length, animals of the crossbred genotype were superior to LW: PR by 4.2%, SR by 1.46%, while the difference in chest girth and body length in SS individuals was not significant. Lung weight was 0.84% higher in PR and 3.7% higher in SR, and kidney weight was 9.8% higher in PR, 6.56% higher in SR, and 1.37% lower in SS. LW animals were superior in heart weight. Behavioral responses (fighting, skirmishing) were more pronounced in the crossed genotypes, especially in SR and SS animals. A higher level of tryptophan was found in the meat of SR crossbred animals, oxyproline — in PR and SR, pH of meat — in Large White PR and SR ranged from 5.61 to 5.72 units, in crossbred animals this indicator did not exceed the values of 5.03–5.21 units. Defects in meat with PSE (pale, soft, exudative) signs of LW were found: in PR — 0.4%, SR — 0.63%, SS — 3.7%, and in LWCL respectively — 2.3%, SR — 2.1%, SS — 4.21%, in local — defects in meat with DFD (dark, firm, dry) signs were manifested in 3.1%, 2.15%, and 5.1%