Study on pig growth hormone gene polymorphisms in western meat-type breeds and Chinese local breeds

Chinese Meishan and Jiangquhai pigs are two of the most prolific pigs in the world, but their growth rate is lower than that of Duroc, Landrace and Pietrain pigs. It is suggested that growth rate is regulated by growth hormone. The objective of the current study was to analyze the porcine growth hormone (p GH) gene polymorphisms based on the polymerase chain reaction restriction fragment-length polymorphism method (PCR-RFLP) for three western meat-type breeds (Duroc, Landrace and Pietrain) and two local Chinese pigs (Meishan and Jiangquhai) . Five polymorphic restriction sites were detected with the ApaI, MspI, BspI and HhaI restriction enzymes in two amplified fragments (605 bp, - 119 to + 486; 506 bp, + 206 to + 711).Breed difference was found only in the 506 bp fragment. There was no difference in allelic frequencies of BspIand HhaI restriction sites among the five breeds ( P > 0.05) . Landrace and Meishan pigs lacked allele G3 of Msp I site. The allele G3 frequency of restriction Msp I site of the 506 bp fragment in Pietrain pigs was higher than that in Duroc and Jianquhai pigs (P < 0.001 ). For ApaI site, the Meishan pigs lacked allele G1 i no difference was found in allelic frequencies among Pietrain, Duroc, Landrace and Jiangquhai pigs (P >0.05) . This new and rapid PCR-RFLP typing method is an attractive tool for analysis of porcine growth hormone gene restriction sites. The differences in MspI and ApaI restriction sites may explain the growth difference between the foreign meat-type breeds above mentioned and local Chinese pigs.

Altered expression of nuclear matrix proteins in etoposide induced apoptosis in HL-60 cells

The events of cell death and the expression of nuclear matrix protein (NMP) have been investigated in a promyelocytic leukemic cell line HL-60 induced with etoposide. By means of TUNEL assay, the nuclei displayed a characteristic morphology change, and the amount of apoptotic cells increased early and reached maximun about 39% after treatment with etoposide for 2 h. Nucleosomal DNA fragmentation was observed after treatment for 4 h. The morphological change of HL-60 cells, thus, occurred earlier than the appearance of DNA ladder. Total nuclear matrix proteins were analyzed by 2-dimensional gel electrophoresis. Differential expression of 59 nuclear matrix proteins was found in 4 h etoposide treated cells. Western blotting was then performed on three nuclear matrix acssociated proteins, PML, HSC70 and NuMA. The expression of the suppressor PML protein and heat shock protein HSC70 were significantly upregulated after etoposide treatment, while NuMA, a nuclear mitotic apparatus protein, was down regulated. These results demonstrate that significant biochemical alterations in nuclear matrix proteins take place during the apoptotic process.

Effect of Copper Toxicity on Lymphoid Organs in Broilers

The experiment was conducted to examine the effect of copper toxicity on lymphoid organs by experimental pathology andflow cytometry (FCM). 180 one-day-old Avian broilers were divided into three groups, and fed diets as follows: 1) Control(Cu 11.97 mg kg-1 diet), 2) Cu- toxic groupⅠ(Cu 650 mg kg-1) and 3) Cu- toxic groupⅡ(Cu 850 mg kg-1) for six weeks.Compared with the control, the growth index of the thymus, spleen and bursa of Fabricius were markedly reduced (P<0.05or P<0.01), the G0/G1 phase of cell cycles of the thymus, spleen and bursa of Fabricius was higher (P<0.05 or P<0.01), whilethe S phase and proliferating index were lower (P<0.05 or P<0.01) in both Cu-toxic group Ⅰ and Cu-toxic group Ⅱ. Theresults demonstrated that Cu toxicity seriously impaired the progression of lymphocytes from the G0/G1 phase to the Sphase, inhibited the growth and development of lymphoid organs.

Effect of Copper Toxicity on Lymphoid Organs in Ducklings

one-day-old Tianfu meat ducklings were divided into three groups, and fed on dietsas follows:(1)control (Cu 12.16 mg kg-1),(2) copper toxicⅠ(Cu 850 mg kg-1) and (3)copper toxicⅡ( Cu 1050 mg kg-1) for studies on effects of copper toxicity on lymphoidorgans in duckling with the methods of experimental pathology and flow cytometry (FCM).The weight and growth index of the thymus, spleen and bursa of Fabricius were markedlyreduced (P<0.05 or P<0.01) in both copper toxic groupⅠand Cu toxic group Ⅱ whencompared with control group. The G0/G1 phase of the cell cycle of the thymus, spleen andbursa of Fabricius was much higher, and S, G2+M phases lower in Cu toxic groupsⅠand Ⅱthan in the control group. There were lymphocyte degeneration and depletion of lymphoidorgans, and the reticular cells of spleen and bursa of Fabricius proliferated and thereticular cells of thymus were also degenerate and necrotic in Cu toxic groups. Theresults demonstrated that Cu toxicity seriously impaired the progression of lymphocytesfrom the G0/G1 phase to S phase, inhibited the development of lymphoid organs and causedmarked pathological injury in lymphoid organs. The results also showed that the effectof Cu toxicity on the primary lymphoid organs occurred stronger than on the secondarylymphoid organs. The effect of Cu toxicity was the greatest on the bursa of Fabricius,followed by the thymus, and then the spleen. Potential mechanisms underlying aforementionedobservation were also discussed.

Studies on Methods and Influencing Factors of Porcine Oocyte Activation

The effects of ionomycin, electrical pulses, dithiothreitol(DTT), 6-DMAP and thimersal, used either alone or in combinations, on the activation rate, pronuclear type and cleavage of porcine oocyte were studied in this paper. The results are as follows:(1)The activation rates of oocytes treated with ionomycin(88.9%)or pulsed(80.0%)alone did not differ significantly from each other and from those in oocytes treated in combination with 6-DMAP(84. 3 and 79. 1%, respectively). While 6-DMAP improved electrical activation(increased the proportion of oocytes with 1 PN), it had no effect on oocyte activation by ionomycin;(2)Post-treatment with DTT significantly enhanced the thimersal activation of porcine oocytes with activation rates increased from 4.6 to 82.6%;(3)When pulsed, the activation rates of oocytes with crimped(85.4%)or fragmented first polar bodies(86. 2%)were significantly higher than those of oocytes with intact polar bodies(58. 8%); the ratio of 1 PN activated oocytes(78. 8%)was significantly higher, but that of 2 PN oocytes(18. 2%)was significantly lower in oocytes with intact polar bodies;(4)The cleavage rate of oocytes activated by electrical stimulus(52.4%)was significantly higher than that in oocytes activated by ionomycin(23.0%)when combined with 6-DMAP, but it was not significantly different from that in oocytes activated by electrical stimulus alone(46.1%).

The Effect of Energy on Serotonin-Like Neurons in Duck Hypothalamus

In the present study, immunohistochemical method (SABC method) was used to examine the distribution of serotonin-like neurons in hypothalamus of Cherry Valley ducks bred with high energy diet and low energy diet respectively. All films were analysed by using a computer-assisted image analysis system. In high energy group, labelled neurons are widely distributed in paraventricular nucleus(PVN, 17.73±1.41 neurons/19.46×103 μm2) and ventromedial hypothalamus (VMH, 15.8±1.71 neurons/19.46×103 μm2); in low energy group, labelled cells are widely distributed in lateral hypothalamus (LH, 11.25±1.53 neurons/19.46×103 μm2), yet there is no positive neuron in PVN. These results indicate that serotonin-like neurons in hypothalamus are involved in the regulation of food intake and energy metabolism.