Twenty castrated male goats, each of Yun-Ling Black goats （YLB goat）, N × YLB hybrid goats （Nubian ♂ ×Yun-Ling Black goats 9） and B × YLB hybrid goats （Boer ♂× Yun-Ling Black goats ♀）, wer...Twenty castrated male goats, each of Yun-Ling Black goats （YLB goat）, N × YLB hybrid goats （Nubian ♂ ×Yun-Ling Black goats 9） and B × YLB hybrid goats （Boer ♂× Yun-Ling Black goats ♀）, were used to evaluate the effect of crossbreeding on the meat chemical composition in the YLB goats of China. After weaning of 90 days, all the experimental goats were reared on natural pasture when they were slaughtered at an age of 730 days. The longissimus dorsi （LD） and biceps femoris （BF） muscles were sampled from each carcass to determine chemical compositions. Both hybrid goats had higher protein content （P 〈 0.01） and lower fat content （P 〈 0.05） than the YLB goats in the two types of muscle. The inosinic acid contents of LD muscle for the YLB goats and the B × YLB hybrid goats were significantly higher （P 〈 0.05） than that for the N × YLB hybrid goats. The LD muscle from the YLB goats contained higher essential amino acid （P 〈 0.01）, total amino acid （P 〈 0.01）, and some individual amino acid （P 〈 0.05） than those from the hybrid goats. The concentration of unsaturated fatty acid （USFA） of LD muscle from the N × YLB hybrid goats was significantly higher than the other two goat breeds （P〈0.05） but did not differ between the other two goat breeds （P〉0.05）. The YLB goats had significantly higher （P〈0.05） concentrations of oleic acid （C18：1） and linolenic acid （C18：3） of LD muscle than the hybrid goats, had significantly higher （P 〈 0.05） proportion of mono-unsaturated （Sum for C 16：1 and C 18：1） than the B ×YLB hybrid goats, and tended to be higher than the N × YLB hybrid goats （P 〉 0.05）. In contrast, the proportion of poly-unsaturated in the YLB goats was significantly lower （P 〈 0.05） than that in the hybrid goats.展开更多
Mite （Varroa destructor） is one of the most serious parasite threats to the honey bee （Apis mellifera） reared in China. The beekeepers mainly use the drug to control and kill the mite in the past years, but the ho...Mite （Varroa destructor） is one of the most serious parasite threats to the honey bee （Apis mellifera） reared in China. The beekeepers mainly use the drug to control and kill the mite in the past years, but the honey products may be contaminated and the mite is becoming drug-resistant. The main idea of this paper is to research the possibility of mite-resistant honeybee rearing by nutritional crossbreed. The larvae （Apis mellifera ligustica） are bred with the royal jelly of Apis carana carana, and then the morphological index of the worker generation, genotypic frequency and gene frequency of the MDH Ⅱ, genetic resemblance, and mite resistance are measured. The results show that： compared to the parent workers, the proboscis length, anterior wing area, the total length of the third and fourth dorsal plate of the abdomen, the length of the fourth dorsal plate of the tuberculum, the area of the sixth abdominal segment, and the area of wax mirrors are significantly different, but the differences in the brachium index, dactylus index, and wing claw are not significant. Moreover, there are some mutations in the genotypic frequency and gene frequency of the MDH Ⅱ. The mite resistance of the nutritional crossbreed worker is significantly higher. The morphological, physical, and biochemical characters, genetic resemblance, and the mite-resistant ability of the worker generation can be changed by nutritional crossbreeding. Nutritional crossbreeding can be a new way to breed the honeybee.展开更多
To understand the fattening performance of Duroc x Landrace×Yorkshire and Duroc×Yorkshire x landrace, 48 individuals of two kinds of three-way crossbreeding lean type commercial pigs were selected to determi...To understand the fattening performance of Duroc x Landrace×Yorkshire and Duroc×Yorkshire x landrace, 48 individuals of two kinds of three-way crossbreeding lean type commercial pigs were selected to determine average daily feed intake, average daily gain and feed gain ratio. The backtat thickness and eye muscle area of pigs were measured at the end of trial. The results showed that Duroc × Landraee × Yorkshire and Dttroc × Yorkshire x Landrace had similar fattening performance, and could be applied under scientific management conditions. The study is of great significance for development of pig industry.展开更多
Mathematical economics is a newly emerging research field resulting from the academic crossbreeding of mathematics and economics. It is a brainchild emerging from the marriage between natural sciences and social scien...Mathematical economics is a newly emerging research field resulting from the academic crossbreeding of mathematics and economics. It is a brainchild emerging from the marriage between natural sciences and social sciences. This article gives a detailed exposition of the discipline’s history, its integration with our country’s socialist market economy and its modem development. The article ultimately explains its application to the comprehensive reclamation of the salinity-plagued agriculture on the Huanghuaihai Plain.展开更多
The reproduction characteristics of 343 sows in six different breeding gxoups wexe anal3nmd to estimate the crcesbreeding parameters. The results indicated that the ovulation rate and the weights of uterus and ovary a...The reproduction characteristics of 343 sows in six different breeding gxoups wexe anal3nmd to estimate the crcesbreeding parameters. The results indicated that the ovulation rate and the weights of uterus and ovary are mainly determined by the additive genetic effects while the nonadditive genetic effects play an important role in embryonal traits and litter perfcm-nance. The heterosis effects in the first litter are larger than those in the second litter becatme of heterosis ac environment interaction. The results also showed the existence of a highly significant maternal heterosis effect on the fertility traits of sows.展开更多
Pinctada martensii is an important shellfish for the production of sea pearls in China.To improve the growth performance of P.martensii,we successfully established three complete diallel crosses using three new variet...Pinctada martensii is an important shellfish for the production of sea pearls in China.To improve the growth performance of P.martensii,we successfully established three complete diallel crosses using three new varieties of P.martensii,which were named Haiyou No.1,Haixuan No.1,and Nanke No.1,to investigate the growth performance of each self-cross line and hybrid line in Beihai,Guangxi Zhuang Autonomous Region,China.Generally,high fertilization and hatching rates were observed in the experiment,suggesting that there was no sperm-egg recognition barrier among these three P.martensii varieties.The survival rate of the self-cross lines was relatively higher than that of hybrid lines,and♀‘Haixuan No.1’×♂‘Haiyou No.1’maintained a high survival rate during the grow-out stage.The shell length and width were affected by the genotypes as well as the interaction between the genotypes and environmental factors on day 400.The variances of the general combining abilities(GCA)and specific combining abilities(SCA)for shell length and width were the result of both additive genetic variance and nonadditive genetic variance.When Haixuan No.1 was the female parent and Nanke No.1 was the male parent,the GCA for shell length and width were both positive on day 400.The heterosis of Haixuan No.1 and Nanke No.1 in terms of shell length and width was positive.From the resulting combining ability and heterosis,♀‘Haixuan No.1’×♂‘Nanke No.1’was considered an ideal hatchery method to improve the growth performance of P.martensii.Our results therefore demonstrated that crossbreeding among these three new varieties can further improve the growth performance of P.martensii.展开更多
基金funded by grants from Ministry of Science and Technology of China (2003BA766C)Yunnan Provincial Government,China (2004NG04)supported by the found for Talented Man Training in Yunnan Province,China (2008PY043)and the research found for scholar coming back from aboard of China Scholarship Council of Ministry of Education of China
文摘Twenty castrated male goats, each of Yun-Ling Black goats （YLB goat）, N × YLB hybrid goats （Nubian ♂ ×Yun-Ling Black goats 9） and B × YLB hybrid goats （Boer ♂× Yun-Ling Black goats ♀）, were used to evaluate the effect of crossbreeding on the meat chemical composition in the YLB goats of China. After weaning of 90 days, all the experimental goats were reared on natural pasture when they were slaughtered at an age of 730 days. The longissimus dorsi （LD） and biceps femoris （BF） muscles were sampled from each carcass to determine chemical compositions. Both hybrid goats had higher protein content （P 〈 0.01） and lower fat content （P 〈 0.05） than the YLB goats in the two types of muscle. The inosinic acid contents of LD muscle for the YLB goats and the B × YLB hybrid goats were significantly higher （P 〈 0.05） than that for the N × YLB hybrid goats. The LD muscle from the YLB goats contained higher essential amino acid （P 〈 0.01）, total amino acid （P 〈 0.01）, and some individual amino acid （P 〈 0.05） than those from the hybrid goats. The concentration of unsaturated fatty acid （USFA） of LD muscle from the N × YLB hybrid goats was significantly higher than the other two goat breeds （P〈0.05） but did not differ between the other two goat breeds （P〉0.05）. The YLB goats had significantly higher （P〈0.05） concentrations of oleic acid （C18：1） and linolenic acid （C18：3） of LD muscle than the hybrid goats, had significantly higher （P 〈 0.05） proportion of mono-unsaturated （Sum for C 16：1 and C 18：1） than the B ×YLB hybrid goats, and tended to be higher than the N × YLB hybrid goats （P 〉 0.05）. In contrast, the proportion of poly-unsaturated in the YLB goats was significantly lower （P 〈 0.05） than that in the hybrid goats.
文摘Mite （Varroa destructor） is one of the most serious parasite threats to the honey bee （Apis mellifera） reared in China. The beekeepers mainly use the drug to control and kill the mite in the past years, but the honey products may be contaminated and the mite is becoming drug-resistant. The main idea of this paper is to research the possibility of mite-resistant honeybee rearing by nutritional crossbreed. The larvae （Apis mellifera ligustica） are bred with the royal jelly of Apis carana carana, and then the morphological index of the worker generation, genotypic frequency and gene frequency of the MDH Ⅱ, genetic resemblance, and mite resistance are measured. The results show that： compared to the parent workers, the proboscis length, anterior wing area, the total length of the third and fourth dorsal plate of the abdomen, the length of the fourth dorsal plate of the tuberculum, the area of the sixth abdominal segment, and the area of wax mirrors are significantly different, but the differences in the brachium index, dactylus index, and wing claw are not significant. Moreover, there are some mutations in the genotypic frequency and gene frequency of the MDH Ⅱ. The mite resistance of the nutritional crossbreed worker is significantly higher. The morphological, physical, and biochemical characters, genetic resemblance, and the mite-resistant ability of the worker generation can be changed by nutritional crossbreeding. Nutritional crossbreeding can be a new way to breed the honeybee.
文摘To understand the fattening performance of Duroc x Landrace×Yorkshire and Duroc×Yorkshire x landrace, 48 individuals of two kinds of three-way crossbreeding lean type commercial pigs were selected to determine average daily feed intake, average daily gain and feed gain ratio. The backtat thickness and eye muscle area of pigs were measured at the end of trial. The results showed that Duroc × Landraee × Yorkshire and Dttroc × Yorkshire x Landrace had similar fattening performance, and could be applied under scientific management conditions. The study is of great significance for development of pig industry.
文摘Mathematical economics is a newly emerging research field resulting from the academic crossbreeding of mathematics and economics. It is a brainchild emerging from the marriage between natural sciences and social sciences. This article gives a detailed exposition of the discipline’s history, its integration with our country’s socialist market economy and its modem development. The article ultimately explains its application to the comprehensive reclamation of the salinity-plagued agriculture on the Huanghuaihai Plain.
文摘The reproduction characteristics of 343 sows in six different breeding gxoups wexe anal3nmd to estimate the crcesbreeding parameters. The results indicated that the ovulation rate and the weights of uterus and ovary are mainly determined by the additive genetic effects while the nonadditive genetic effects play an important role in embryonal traits and litter perfcm-nance. The heterosis effects in the first litter are larger than those in the second litter becatme of heterosis ac environment interaction. The results also showed the existence of a highly significant maternal heterosis effect on the fertility traits of sows.
基金funded by the National Natural Science Foundation of China(No.911221680).
文摘Pinctada martensii is an important shellfish for the production of sea pearls in China.To improve the growth performance of P.martensii,we successfully established three complete diallel crosses using three new varieties of P.martensii,which were named Haiyou No.1,Haixuan No.1,and Nanke No.1,to investigate the growth performance of each self-cross line and hybrid line in Beihai,Guangxi Zhuang Autonomous Region,China.Generally,high fertilization and hatching rates were observed in the experiment,suggesting that there was no sperm-egg recognition barrier among these three P.martensii varieties.The survival rate of the self-cross lines was relatively higher than that of hybrid lines,and♀‘Haixuan No.1’×♂‘Haiyou No.1’maintained a high survival rate during the grow-out stage.The shell length and width were affected by the genotypes as well as the interaction between the genotypes and environmental factors on day 400.The variances of the general combining abilities(GCA)and specific combining abilities(SCA)for shell length and width were the result of both additive genetic variance and nonadditive genetic variance.When Haixuan No.1 was the female parent and Nanke No.1 was the male parent,the GCA for shell length and width were both positive on day 400.The heterosis of Haixuan No.1 and Nanke No.1 in terms of shell length and width was positive.From the resulting combining ability and heterosis,♀‘Haixuan No.1’×♂‘Nanke No.1’was considered an ideal hatchery method to improve the growth performance of P.martensii.Our results therefore demonstrated that crossbreeding among these three new varieties can further improve the growth performance of P.martensii.
