A starvation trial was conducted to determine compensatory growth of the juvenile golden pompano Trachinotus ovatus which were deprived of food for 1, 2, 5 and 7 days respectively. The results of tests in outdoor ceme...A starvation trial was conducted to determine compensatory growth of the juvenile golden pompano Trachinotus ovatus which were deprived of food for 1, 2, 5 and 7 days respectively. The results of tests in outdoor cement pools and net pens showed that, in the first 15 days and 30 days, the growth of 1 day and 2 days-deprived groups was probably the same with that of control group, which accorded with fully compensatory description. However, the weight of 5 days and 7 days-deprived fingerlings were lower than that of the control group, which accorded with the description of the partial compensatory growth. As the starvation prolonged, feed conversion efficiency of the starved groups increased and was higher than the control group. Meanwhile, feeding rate also increased, but the fish of 1 day and 2 days-deprived groups was lower than that of the control group, and feeding quantity reduced and was lower than that of the control group. It suggested that the mechanism of compensatory growth was mainly due to improving feed conversion efficiency. Fish biochemical composition was analyzed: the water content and ash of fish sample increased due to starvation, while the lipid and protein decreased. The loss of lipid was greater than that of the protein, and the biochemical composition of fish in each group was restored to the control level by the end of the experiment. It suggested that Trachinotus ovatus may mainly consume lipid during the period of starvation.展开更多
Background: The objective of this study was to investigate the effect of dietary restriction and subsequent compensatory growth on the relative expression of genes involved in volatile fatty acid transport, metabolis...Background: The objective of this study was to investigate the effect of dietary restriction and subsequent compensatory growth on the relative expression of genes involved in volatile fatty acid transport, metabolism and cell proliferation in ruminal epithelial tissue of beef cattle. Sixty Holstein Friesian bulls(mean liveweight 370 ± 35 kg;mean age 479 ± 15 d) were assigned to one of two groups:(i) restricted feed allowance(RES; n = 30) for 125 d(Period 1) followed by ad libitum access to feed for 55 d(Period 2) or(ii) ad libitum access to feed throughout(ADLIB; n = 30). Target growth rate for RES was 0.6 kg/d during Period 1. At the end of each dietary period, 15 animals from each treatment group were slaughtered and ruminal epithelial tissue and liquid digesta harvested from the ventral sac of the rumen. Real-time q PCR was used to quantify m RNA transcripts of 26 genes associated with ruminal epithelial function. Volatile fatty acid analysis of rumen fluid from individual animals was conducted using gas chromatography.Results: Diet × period interactions were evident for genes involved in ketogenesis(BDH2, P = 0.017), pyruvate metabolism(LDHa, P = 0.048; PDHA1, P = 0.015) and cellular transport and structure(DSG1, P = 0.019; CACT, P = 0.027). Ruminal concentrations of propionic acid(P = 0.018) and n-valeric acid(P = 0.029) were lower in RES animals, compared with ADLIB, throughout the experiment. There was also a strong tendency(P = 0.064)toward a diet × period interaction for n-butyric with higher concentrations in RES animals, compared with ADLIB, during Period 1.Conclusions: These data suggest that following nutrient restriction, the structural integrity of the rumen wall is compromised and there is upregulation of genes involved in the production of ketone bodies and breakdown of pyruvate for cellular energy. These results provide an insight into the potential molecular mechanisms regulating ruminal epithelial absorptive metabolism and growth following nutrient restriction and subsequent compensatory growth.展开更多
Degradation of meadow ecosystems in the largest alpine region of the world,i.e.,the Qinghai-Tibetan Plateau(QTP),is a crucial ecological issue that has ardently discussed in recent years.Many factors,such as livestock...Degradation of meadow ecosystems in the largest alpine region of the world,i.e.,the Qinghai-Tibetan Plateau(QTP),is a crucial ecological issue that has ardently discussed in recent years.Many factors,such as livestock overgrazing,climate change and overpopulation of small mammals are treated as important factors that cause the degradation of meadow ecosystems in the QTP.However,there are few hypotheses focus on the potential role of plant compensatory growth on meadow degradation.We proposed a compensatory growth-related hypothesis to understand the potential degradation process of meadow ecosystems in the QTP.We discussed that there are two stages of meadow degradation,i.e.the beginning stage of meadow degradation that is triggered by high-strength overcompensation;and the intensification stage of meadow degradation,which are driven by external factors such as climate warming,small mammals and thawing of permafrost.The mechanism of meadow degradation driven by plant compensatory growth is the asynchronism of plant consumption and the availability of soil nutrients.Our hypothesis that plant compensatory growth drives meadow degradation under the overgrazing condition requires re-examination and modification by testing the balance between soil nutrient cycling rates and the strength of plant compensatory growth in alpine regions.展开更多
Plough pans (PPs), common in the black-soil region of northeastern China, have significant effects on the root systems of crops. We conducted a field experiment to study the distribution of soybean roots under the i...Plough pans (PPs), common in the black-soil region of northeastern China, have significant effects on the root systems of crops. We conducted a field experiment to study the distribution of soybean roots under the influence of PPs. The soybean roots showed compensatory growth above the PP, with higher root length and weight in soil with a PP compared to those without a PP. Roots were heavier and longer in the 15-75 cm soil layer without a PP than with a PP. Soil porosity was lower in the PP and the soil below the PP, which likely decreased the oxygen content of the soil and induced more growth of roots above the PP. The PP is also likely to decrease infiltration of rain-water and hinder the migration of nitrate downward, which in turn increased the density and length of soybean root hairs, which, hence, promoted growth.展开更多
基金Supported by Ocean Public Welfare Scientific Research Project,State Oceanic Administration of the People's Republic of China(Grant No.201205028)Key Projects in the National Science&Technology Pillar Program during the Twelfth Five-year Plan Period(2011BD13B11)Hainan Scientific Operating Expense Projects and Major Project of Science and Technology(ZDZX2013009,ZDZX2013014)
文摘A starvation trial was conducted to determine compensatory growth of the juvenile golden pompano Trachinotus ovatus which were deprived of food for 1, 2, 5 and 7 days respectively. The results of tests in outdoor cement pools and net pens showed that, in the first 15 days and 30 days, the growth of 1 day and 2 days-deprived groups was probably the same with that of control group, which accorded with fully compensatory description. However, the weight of 5 days and 7 days-deprived fingerlings were lower than that of the control group, which accorded with the description of the partial compensatory growth. As the starvation prolonged, feed conversion efficiency of the starved groups increased and was higher than the control group. Meanwhile, feeding rate also increased, but the fish of 1 day and 2 days-deprived groups was lower than that of the control group, and feeding quantity reduced and was lower than that of the control group. It suggested that the mechanism of compensatory growth was mainly due to improving feed conversion efficiency. Fish biochemical composition was analyzed: the water content and ash of fish sample increased due to starvation, while the lipid and protein decreased. The loss of lipid was greater than that of the protein, and the biochemical composition of fish in each group was restored to the control level by the end of the experiment. It suggested that Trachinotus ovatus may mainly consume lipid during the period of starvation.
基金funded through Science Foundation Ireland(SFI)contract no 09/RFP/GEN2447
文摘Background: The objective of this study was to investigate the effect of dietary restriction and subsequent compensatory growth on the relative expression of genes involved in volatile fatty acid transport, metabolism and cell proliferation in ruminal epithelial tissue of beef cattle. Sixty Holstein Friesian bulls(mean liveweight 370 ± 35 kg;mean age 479 ± 15 d) were assigned to one of two groups:(i) restricted feed allowance(RES; n = 30) for 125 d(Period 1) followed by ad libitum access to feed for 55 d(Period 2) or(ii) ad libitum access to feed throughout(ADLIB; n = 30). Target growth rate for RES was 0.6 kg/d during Period 1. At the end of each dietary period, 15 animals from each treatment group were slaughtered and ruminal epithelial tissue and liquid digesta harvested from the ventral sac of the rumen. Real-time q PCR was used to quantify m RNA transcripts of 26 genes associated with ruminal epithelial function. Volatile fatty acid analysis of rumen fluid from individual animals was conducted using gas chromatography.Results: Diet × period interactions were evident for genes involved in ketogenesis(BDH2, P = 0.017), pyruvate metabolism(LDHa, P = 0.048; PDHA1, P = 0.015) and cellular transport and structure(DSG1, P = 0.019; CACT, P = 0.027). Ruminal concentrations of propionic acid(P = 0.018) and n-valeric acid(P = 0.029) were lower in RES animals, compared with ADLIB, throughout the experiment. There was also a strong tendency(P = 0.064)toward a diet × period interaction for n-butyric with higher concentrations in RES animals, compared with ADLIB, during Period 1.Conclusions: These data suggest that following nutrient restriction, the structural integrity of the rumen wall is compromised and there is upregulation of genes involved in the production of ketone bodies and breakdown of pyruvate for cellular energy. These results provide an insight into the potential molecular mechanisms regulating ruminal epithelial absorptive metabolism and growth following nutrient restriction and subsequent compensatory growth.
基金This work was supported by the National Natural Science Foundation of China[31901394]the Second Tibetan Plateau Scientific Expedition and Research[2019QZKK0307]Young Elite Scientists Sponsorship Program by CAST[2019QNRC001].
文摘Degradation of meadow ecosystems in the largest alpine region of the world,i.e.,the Qinghai-Tibetan Plateau(QTP),is a crucial ecological issue that has ardently discussed in recent years.Many factors,such as livestock overgrazing,climate change and overpopulation of small mammals are treated as important factors that cause the degradation of meadow ecosystems in the QTP.However,there are few hypotheses focus on the potential role of plant compensatory growth on meadow degradation.We proposed a compensatory growth-related hypothesis to understand the potential degradation process of meadow ecosystems in the QTP.We discussed that there are two stages of meadow degradation,i.e.the beginning stage of meadow degradation that is triggered by high-strength overcompensation;and the intensification stage of meadow degradation,which are driven by external factors such as climate warming,small mammals and thawing of permafrost.The mechanism of meadow degradation driven by plant compensatory growth is the asynchronism of plant consumption and the availability of soil nutrients.Our hypothesis that plant compensatory growth drives meadow degradation under the overgrazing condition requires re-examination and modification by testing the balance between soil nutrient cycling rates and the strength of plant compensatory growth in alpine regions.
基金supported by the National Natural Science Foundation of China (51239009,41301288,51479032 and 51409213)the Postdoctoral Science Foundation of China (2014M561317)+2 种基金the Heilongjiang Postdoctoral Financial Assistance,China (LBH-Z13023)the Heilongjiang Provincial Department of Education Science and Technology Research Project,China (12541039)the Young Talents Project of Northeast Agricultural University,China (14QC48)
文摘Plough pans (PPs), common in the black-soil region of northeastern China, have significant effects on the root systems of crops. We conducted a field experiment to study the distribution of soybean roots under the influence of PPs. The soybean roots showed compensatory growth above the PP, with higher root length and weight in soil with a PP compared to those without a PP. Roots were heavier and longer in the 15-75 cm soil layer without a PP than with a PP. Soil porosity was lower in the PP and the soil below the PP, which likely decreased the oxygen content of the soil and induced more growth of roots above the PP. The PP is also likely to decrease infiltration of rain-water and hinder the migration of nitrate downward, which in turn increased the density and length of soybean root hairs, which, hence, promoted growth.