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Responses of mammary amino acid metabolism and aminopeptidase N gene expression to duodenal soybean small peptides and infusion of free amino acids in lactating goats

100%

Liu H., Wang L., Wang L.-B., Li S.-L., Cao Z.-J.

Journal of Animal and Feed Sciences

2010

tom 19

nr 1

24-36

The duodenal perfusion technique was used to determine whether small peptides were more effective than free amino acids (FAA) for milk protein synthesis and to investigate the effects of infusing soyabean small peptides (SSP) or their FAA on the mammary amino acid (AA) metabolism of lactating goats. Six Saanen goats with silicon catheters implanted into their carotid artery and mammary veins were used in a Latin square design. Blood samples were collected from the carotid artery and mammary vein. The AA concentrations in the plasma, as well as mammary AA uptakes were monitored. The results showed that the concentrations of most essential amino acids (EAA) were significantly higher (P<0.05) in the FAA infusion treatment as compared with the SSP treatment, except for Val, Ile, and Met. The concentration of most of the non-essential amino acids (NEAA), measured after FAA infusion, was highest (P<0.05) when compared with the SSP treatment and the controls. The mammary uptake of most of EAA in the FAA infusion group was higher in comparison with the SSP infusion group. The mammary uptake to milk output ratios of EAA (except for Met) were low in the SSP treatment, compared with the FAA treatment. Significant increases in milk protein yield and milk protein content in the FAA infusion treatment were observed (P<0.05). In the SSP infusion treatment, milk yield and milk protein were numerically increased compared with the control. The abundance of aminopeptidase N (APN) mRNA in mammary tissue was 38.28 in the SSP infusion group, and 2.83, 5.28 in the control and FAA infusion treatment, respectively. In conclusion, the data suggest the FAA was more effective for milk protein synthesis, while the activity of APN was related to utilization of small peptides by the mammary gland.

Can Potentilla fruticosa Linn. shrubs facilitate the herb layer of heavily grazed pasture on the Eastern Tibetan Plateau?

100%

LI P.-X., Krusi B. O., Li S.-L., Cai X.-H., Yu F.-H.

Polish Journal of Ecology

2011

tom 59

nr 1

The facilitative and competitive effects of shrubs on herbaceous species have been extensively studied, but little is known about the roles of the shrub distribution patterns in such effects. On a heavily grazed pasture on the Tibetan Plateau, we investigated the effects of Potentilla fruticosa Linn. shrubs of different distribution patterns on the small-scale vegetation pattern of the herb layer. We made same-sized releves at five micro-site types, i.e., beneath and outside the canopies of solitary Potentilla individuals, beneath and outside the canopies of edge-of-patch individuals and at the central openings of torusshaped large Potentilla patches. Shrubs protected certain species by increasing their frequencies of occurrence or flowering. However, only few species benefited from shrubs and more occurred or flowered more frequently outside. The data at community level indicated that species richness and diversity index were higher outside. The patch openings did not benefit species richness, pooled cover, diversity index or evenness of central vegetations. No special species was found growing beneath shrubs exclusively and few species were found with higher occurrences beneath shrubs. Furthermore, no significant difference was found between the two different distribution patterns at either community or species level. Vegetation ordinations confirmed this and vegetations beneath and outside the shrubs were distinguished merely. In conclusion, Potentilla facilitated some species in the herb layer and the patch openings did not show large protective effects. Also, distribution patterns of Potentilla did not affect the difference between vegetations beneath and outside shrub canopies.

Ograniczanie wyników

1 Journal of Animal and Feed Sciences

1 Polish Journal of Ecology

2 Li S.-L.

1 Cai X.-H.

1 Cao Z.-J.

1 Krusi B. O.

1 LI P.-X.

1 Liu H.

1 Wang L.

1 Wang L.-B.

1 Yu F.-H.

1 2011

1 2010

Wyniki wyszukiwania

Responses of mammary amino acid metabolism and aminopeptidase N gene expression to duodenal soybean small peptides and infusion of free amino acids in lactating goats

Can Potentilla fruticosa Linn. shrubs facilitate the herb layer of heavily grazed pasture on the Eastern Tibetan Plateau?