Effects of nesfatin-1 on food intake and LH secretion in prepubertal gilts and genomic association of the porcine NUCB2 gene with growth traits

Nesfatin-1, a product of the nucleobindin 2 (NUCB2) gene, purportedly plays important roles in whole-body energy homeostasis. Experiments were conducted to determine how NUCB2 expression in fat depots may be controlled in the pig and to test the hypothesis that nesfatin-1 regulates appetite and LH secretion in the gilt. Prepubertal gilts were used to study expression of NUCB2 in fat and the effects of intracerebroventricular (i.c.v.) injection of nesfatin-1 on food intake and pituitary hormone secretion. Growing pigs (gilts and barrows at 22 wk of age, n = 1,145) or sexually mature gilts (n = 439) were used to test association of SNP in the NUCB2 gene with growth traits. The expression of NUCB2 was similar for subcutaneous fat compared with perirenal fat. An i.c.v. injection of the melanocortin-4 receptor agonist [Nle⁴, d-Phe⁷]-α-melanocyte-stimulating hormone did not alter expression of NUCB2 mRNA in the hypothalamus but reduced (P = 0.056) NUCB2 mRNA expression in subcutaneous fat. Short-term (7 d) submaintenance feeding reduced (P < 0.05) BW and did not alter expression of mRNA for NUCB2, visfatin, or leptin but increased (P < 0.05) expression of adiponectin mRNA in fat. Central injection of nesfatin-1 suppressed (P < 0.001) feed intake. Secretion of LH was greater (P < 0.01) after i.c.v. injection of nesfatin-1 than after saline. Single nucleotide polymorphisms in the porcine NUCB2 gene were not associated with adiposity of growing pigs or age at puberty in gilts but were associated (P < 0.05) with BW at puberty. These data indicate that NUCB2 is expressed in fat depots of the pig and that the level of expression is sensitive to stimulation of appetite-regulating pathways in the hypothalamus. It is confirmed herein that nesfatin-1 can regulate appetite in the pig and affect the gonadotropic axis of the prepubertal pig. Association of SNP in the porcine NUCB2 gene with BW at puberty suggests that regulation of appetite by nesfatin-1 in the pig affects growth, which may have important consequences for adult phenotypes.     

Inhibited development of trichostrongylid worms in grazing cattle

Inhibition of development of gastro-intestinal trichostrongylid worms was studied using successive groups of tracer calves and groups of continuously grazed calves over one year in the Tully area of North Queensland lowland wet tropics. The results, assessed by means of worms from these calves recovered at necropsy 3 weeks after their removal from pastures, showed inhibition in the development of Haemonchus placei and Cooperia punctata at the early fourth stage at the approach to and during the relatively dry period in the area. Inhibition was however minor and inhibited larvae formed but only a small percentage of worm burdens in both categories of calves, indicating that they were not in any way of major epidemiological importance. It was suggested that the minor nature of inhibition was due to the mild climatic conditions which could not produce appropriate conditioning treatment, or caused only mild selection pressure for inhibition in the area.     

Enzyme histochemical studies in an ontogeny study of muscle development in Ossabaw and decapitated fetuses: cellular reactions

Fetuses were decapitated in one uterine horn in each of 14 sows at 45 d of gestation. Control (C) and decapitated (D) fetuses were removed by Caesarean section from three sows at 65 d of gestation (total of 10 D and 10 C fetuses), two sows at 85 d (six D and six C fetuses) and nine sows at 110 d (nine C and nine D fetuses) of gestation (Exp. 1). In Exp. 2, four to six fetuses were removed from each of two Ossabaw (O) gilts and three crossbred (C, Landrace X Yorkshire) gilts at 70 d of gestation, from three C and O gilts at 90 d of gestation and from three C and two O gilts at 110 d of gestation. In Exp. 1, one semitendinosis muscle was removed for histochemistry, whereas the contralateral muscle was removed and weighed. A medial portion of biceps femoris muscle was removed and used for histochemistry in Exp. 2. In both experiments, transverse sections (cryostat) of muscle were stained for lipid, glycogen (PAS) and the following enzymes: acid ATPase, NADH-TR, NADPH-TR, malate dehydrogenase (NAD- and NADP-dependent reactions; MDH), succinate dehydrogenase (SDH), alpha-glycerol phosphate dehydrogenase (with and without NAD; alpha-GPDH), isocitrate dehydrogenase (NAD dependent; ICDH), esterase, lipoprotein lipase and lipase. In Exp. 1, body and muscle weights of the two groups were not significantly different (P greater than .05) at 65 d of gestation, whereas D fetuses were smaller and had lighter weight muscles (P less than .05) at 85 d of gestation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of ractopamine on insulin sensitivity and response of isolated rat adipocytes

In vitro effects of the phenethanolamine ractopamine on basal and insulin-stimulated lipid metabolism were determined in adipocytes isolated from epididymal fat pads of Sprague-Dawley rats. Ractopamine appeared to be equipotent to the catecholamine isoproterenol in stimulating basal lipolysis and inhibiting basal lipogenesis, producing maximum effects at 10(-6) M. Addition of a half-maximally stimulating dose of ractopamine (5 x 10(-8) M) to the incubation media decreased insulin sensitivity but not insulin responsiveness of the cells, stimulating lipolysis and inhibiting lipogenesis only in the presence of low media insulin concentrations. This effect was totally reversed by 10 microM/propranolol. Maximally effective concentrations of ractopamine (10(-6) M) significantly decreased both the sensitivity and responsiveness of the isolated adipocytes to insulin. Addition of 10 microM propranolol to the incubation media effectively reversed the lipolytic and anti-lipogenic effects of 10(-6) M ractopamine observed at media insulin concentrations greater than 25 microU/ml, whereas it only partially reduced the ractopamine-induced effects observed at lower insulin concentrations. The results demonstrate 1) that ractopamine has concentration-dependent effects on adipose tissue insulin sensitivity and responsiveness and 2) that these effects may be mediated, in part, through beta-adrenergic receptors.     

The interaction of hydrocortisone and thyroxine during fetal adipose tissue differentiation: CCAAT enhancing binding protein expression and capillary cytodifferentiation.

Late-term fetal pigs from genetically obese dams have elevated levels of thyroid hormones and glucocorticoids, depressed levels of GH, larger fat cells and elevated lipogenesis than do fetal pigs from lean dams. We investigated the influence of elevated levels of thyroid hormones and glucocorticoids per se on adipose tissue traits by chronically treating hypophysectomized (hypox; d 70) fetal pigs between d 90 and 105 of gestation with either thyroxine (T4), hydrocortisone (HC), or the combination of T4 + HC. Treatment with T4 and T4 + HC increased serum T4 and IGF-I levels and enhanced skin and hair development. Treatment with HC and T4 + HC increased serum HC levels, fat cell size, and inner subcutaneous adipose tissue thickness. Quantitative analysis of stained adipose tissue sections indicated that T4 + HC treatment increased lipid accretion and fat cell cluster development more than did either hormone alone. The T4 + HC markedly increased apparent fat cell number, because there was only a 19% increase in fat cell size. A hypox-induced deficit in cytodifferentiation of capillaries associated with adipocytes was not influenced by T4, but was partially normalized by treatment with HC and T4 + HC. Immunocytochemical and Western blot analyses showed no influence of hormonal treatment on expression of three CCAAT enhancing binding protein (C/EBP) isoforms. However, expression of C/EBPdelta in adipose tissue was markedly reduced in control fetal pigs compared with hypox fetal pigs. These studies indicate that concurrent action of glucocorticoids and thyroid hormones may be the critical aspect of endocrine regulation of fetal adipogenesis.     

Biochemical and morphological characterization of potato clones differing in their resistance to late blight

Summary Morphological and biochemical parameters that could be involved in resistance to late blight were studied in non-infected and in infected potato hybrids resulting from a cross betweenSolanum phureja, resistant toPhytophthora infestans, and a susceptibleSolanum tuberosum. Some morphological differences between resistant and susceptible hybrids, indicating a positive correlation between stem diameter and phloem thickness in the stem and resistance toP. infestans, were observed. The lignin content in the leaves of the resistant hybrid rose upon infection byP. infestans. In the leaves of the susceptible hybrid, a diminution of the lignin content could be observed upon infection byP. infestans. In the same context, peroxidasic activity raised upon infection byP. infestans in both resistant and susceptible hybrids. Further characterization of the hybrid clones based on the polymorphism of peroxidases was attempted using isoelectric focusing.     

Benign cranial mediastinal lesions in three cats

Cranial mediastinal lesions were detected in three cats, associated with respiratory impairment (case one), spontaneous pneumothorax (case two) and myasthenia gravis (case three), respectively. On gross and histological examination, the first case was considered either a lymphangioma or a branchial cystic mass of the thymic region of the mediastinum; a cystic lesion was suggested by sonographic detection of multiple anechoic cavitations within a circumscribed mass, while fine needle aspiration cytology excluded lymphosarcoma. The second case was diagnosed histologically as a cystic thymoma, but the third case was not examined microscopically. The masses were amenable to surgical excision in the first two cats, while this proved unnecessary in the third case because of resolution following treatment with dexamethasone. Corticosteroid responsiveness was unhelpful in distinguishing between these benign lesions and lymphosarcoma, as in two cases there was a partial or complete response to dosing with prednisolone or dexamethasone. These cases are presented to emphasise that conditions other than lymphosarcoma can produce cranial mediastinal lesions in cats, and that the prognosis for surgical treatment of lymphangiomas, multilocular thymic cysts and cystic thymomas can be excellent.     

Responsiveness to adipogenic agents in stromal-vascular cultures derived from lean and preobese pig fetuses: an ontogeny study.

Primary cultures of stromal-vascular (S-V) cells from adipose tissue were used to evaluate characteristics of preadipocytes from lean and preobese fetuses at several ages (50, 75, and 110 d). In insulin-supplemented (1 microM) cultures (serum free) there was a significant age x fetal genotype interaction (P less than .01) for glycerol-phosphate dehydrogenase specific activity (GPDH); GPDH activity was genotype-dependent at 110 d (preobese greater than lean). The responses of S-V cultures (preadipocyte development) to 2% pig serum and to insulin (serum free) were similar. Main effects of genotype and age were significant (P less than .05) for protein levels in pig serum and insulin-treated cultures. There was a significant genotype x age (P less than .05) interaction for GPDH activity and protein levels in cultures treated with dexamethasone + 3-isobutyl-1-methylxanthine (DEX-IBMX). Treatment with DEX-IBMX induced more preadipocyte development in cultures from preobese fetuses than in cultures from lean fetuses at 110 d (P less than .05). The responsiveness of S-V cultures to DEX-IBMX (enhanced development) increased considerably between 50 and 75 d regardless of fetal genotype, but there was little response in cultures form 50-d fetuses. Preadipocyte development in lean and preobese fetuses diverged between 75 and 110 d, resulting in many more preadipocytes in preobese fetuses at 110 d. Therefore, S-V cells from preobese fetuses (late term) may be inherently more sensitive to adipogenic agents than S-V cells from lean fetuses.