Could the pale, soft, and exudative condition be explained by distinctive histological characteristics?1

Pork quality depends on various genetic and environmental factors. Despite the improvement of slaughter conditions, the PSE type is still one of the main concerns in this field. This study was conducted on nonstressed animals to evaluate the tissue characteristics of some muscles usually involved during stress compared with a reference muscle, the M. triceps brachii, which is actually not subject to stress-caused damages. Samples of M. triceps brachii, M. longissimus dorsi, M. biceps femoris, and M. semimembranosus were taken from pigs exhibiting 1 of the 3 HAL genotypes (NN, Nn, or nn) and 2 of the 3 RN genotypes (rn+rn+ or rn+RN-). Histoenzymology and immunohistochemistry were used to compare the fiber typing and capillary network in these muscles within these different stress susceptibility genotypes. In comparison with the reference muscle, M. triceps brachii, the combination of a high value of the number of type IIb fibers and a low vascular network showed a primary effect on muscles usually involved during stress. This led to the definition of a PSE index. A dramatic increase (P < 0.001) in this PSE index was systematically found in muscles usually involved in the PSE-type condition. These results show that distinctive histological characteristics were associated with the vulnerability of some muscles independently of the genotypes. Moreover, this study highlights the distinctive histological features of each genotype and is likely to suggest some interactions between them.

Restoration of ovarian steroid secretion and histologic assessment after freezing, thawing, and autograft of a hemi-ovary in sheep

OBJECTIVE

To evaluate the effects of freezing, thawing, and autograft of a hemi-ovary on steroid secretion, endometrial maturation, and ovarian histology in ewes.

DESIGN

Experimental animal study.

SETTING

Laboratoire de Zootechnie, Ecole Nationale Vétérinaire, Marcy l'Etoile, France.

ANIMAL(S)

Six lambs aged 6 months to 1 year old.

INTERVENTION(S)

Hemi-ovaries were prepared and frozen from the right ovary of six lambs and autografted 4 weeks later to the contralateral ovarian hilus. The autografts and the uterus were recovered 1 year later. Blood tests were performed each week to measure P concentration.

MAIN OUTCOME MEASURE(S)

Number of primordial follicles; levels of plasma P.

RESULT(S)

Histologic examination of ovarian slices after freezing showed no destruction of primordial, primary, secondary, or cavitary follicles. The frozen ovarian autograft showed good recovery of the macroscopic and microscopic ovarian structure. After autografting, histologic examination revealed primordial to cavitary follicles. Secretion of P started to rise 4 weeks after the autograft. Histologic analysis of the endometrium showed numerous glands, vessels, and mucous secretion.

CONCLUSION(S)

Frozen ovarian autografts achieved P secretion and endometrial maturity.