Length Gain Rate Research Articles

Combined effects of carbonate alkalinity and pH on survival, growth and haemocyte parameters of the Venus clam Cyclina sinensis

Carbonate alkalinity (CA) and pH are considered to be two important stress factors that determine the response of aquatic animals to sudden transfers into saline-alkaline water. To evaluate the potential for aquaculture production of Venus clams (Cyclina sinensis) farmed in saline-alkaline water, the combined effects of CA (2.5 (control), 10.0, 20.0 and 40.0 meq/l) and pH (8.0 (control), 8.5, 9.0 and 9.5) on survival rate was monitored every day for 10 days. Length gain rate (LGR) and weight gain rate (WGR) were also monitored for two months, and total haemocyte count (THC), phagocytic rate (PR) and haemocyte mortality (HM) were measured for 3, 6, 12 and 24 days under the same water temperature (20 °C) and salinity (15‰) conditions. The results showed that survival rates in treatments of CA ≤ 20.0, combined with pH ≤ 9.0, were 100%. LGR and WGR in treatments of CA 2.5 & pH 8.0 (control), CA 2.5 & pH 8.5 and CA 10.0 & pH 8.0 exhibited the largest values (P > 0.05), while in other treatments, they showed a decreasing trend with an increase in either CA or pH or both (P < 0.05). Similarly, for THC, PR and HM, no significant differences were observed among the fast growth treatments during the entire experimental period (P > 0.05), however, in other treatments, they presented significant differences, especially on day 3 and 6 (P < 0.05), most notably with increases in CA or pH, but returned to control levels on day 12. In conclusion, in this study, a strong interaction between CA and pH was observed. Additionally, it was ascertained that the Venus clam C. sinensis can withstand the stress of CA 20.0 combined pH 9.0, although individuals grows slowly and may take approximately 12 days to recover to the unstressed condition.

Excess Early Postnatal Weight Gain Leads to Thicker and Stiffer Arteries in Young Children

Although early life growth pattern is associated with cardiovascular disease later in life, it is unknown whether vascular changes associated with excess early weight gain already occur in early childhood. In the Wheezing-Illnesses-Study-Leidsche-Rijn (WHISTLER) birth cohort, weight and height from birth to 3 months of age were used to calculate Z-scores of individual weight and length gain rates. In the first 333 children who turned 5 years old, intima-media thickness, distensibility, and elastic modulus of the carotid artery were measured ultrasonographically. The association between weight gain rate for length gain rate (WLG), as a measure of excess weight gain, and vascular characteristics was assessed by generalized linear modeling. Interaction between birth size and WLG was tested. Per 1 SD increase in WLG, carotid intima-media thickness was 5.1 μm (95% confidence interval, 1.0-9.2; P value = .01) higher (adjusted for age, gender, current height, and observer). The thinner the children were at birth, the stiffer the arteries were with increasing WLG (interaction between birth size and WLG-distensibility: P = .04; elastic modulus: P = .03). Excess early postnatal weight gain leads to vascular changes already in early childhood, characterized by thicker arterial walls. In children who are relatively thin at birth, excess early postnatal weight gain also leads to stiffer arteries. This supports the view that cardiovascular disease risk is associated with growth pattern early in life.

Excess early postnatal weight gain leads to increased abdominal fat in young children.

Background. Increased childhood weight gain has been associated with later adiposity. Whether excess early postnatal weight gain plays a role in childhood abdominal fat is unknown. Design. In the ongoing Wheezing Illnesses Study Leidsche Rijn (WHISTLER), birth cohort weight and length from birth to age 3 months were obtained. In the first 316 five-year-olds, intra-abdominal and subcutaneous fat were measured ultrasonographically. Individual weight and length gain rates were assessed in each child. Internal Z-scores of weight for length gain (WLG) were calculated. Multiple imputation was used to deal with missing covariates. Results. Per-1-unit increase in Z-score WLG from birth to 3 months, BMI, waist circumference, and subcutaneous fat were significantly higher; 0.51 kg/m2, 0.84 cm, and 0.50 mm, respectively. After multiple imputation, a trend towards significance was observed for intra-abdominal fat as well (0.51 mm/SD). In the associations with 5-year adiposity, no interaction between postnatal Z-score WLG and birth size was found. Conclusion. Excess early postnatal weight gain is associated with increased general and central adiposity, characterized by more subcutaneous and likely more intra-abdominal fat at 5 years of age.

Development of transgenic zooplankton Artemia as a bioreactor to produce exogenous protein

Although the crustacean Artemia has been commonly used as an experimental organism and served as a live bait feed for aquaculture, gene transfer system on Artemia sp. to generate stable lines is not well developed. In this study, we optimized a condition for cyst-eletroporation and generated stable lines of transgenic A. sinica. Two expression plasmids directed by the hybrid promoters of cytomegalovirus (CMV) and medaka β-actin (Mβ) were co-electroporated on decapsulated cysts: pCMV-Mβ-GFP contained GFP reporter gene and pCMV-Mβ-ypGH contained yellowfin porgy GH (ypGH) cDNA. We examined the GFP shown in the Artemia larvae and found that the expression rate was 13.3% (3,219 out of 24,054 examined). We then chose 200 G0 founders which strongly expressed GFP to generate transgenic lines. Homozygotic strains derived from F4 generation of each transgenic line, A3 and A8, were obtained. We proved that transgenic lines A3 and A8 also harbored pCMV-Mβ-ypGH and produced recombinant ypGH with a concentration of 0.089 and 0.032μg per 50 homozygotic nauplii, respectively. Ten live Artemia nauplii were fed daily to zebrafish larvae during 25 to 35days of post-fertilization. The average body length gain rates of zebrafish larvae fed transgenic Artemia were 16-20% greater than those of control group, indicating the exogenous ypGH produced by transgenic Artemia is functional. Therefore, we concluded that the transgenesis on Artemia is developed, and transgenic Artemia might be highly potentially useful as a new bioreactor material for application in aquaculture and biological researches.

Effects of anthraquinones extracted from Rheum officinale Bail on the growth, non-specific immune response of Macrobrachium rosenbergii

The effects of anthraquinone extracted from Rheum officinale Bail on growth, some non-specific immunite parameters, and disease resistance of Macrobrachium rosenbergii were studied in this experiment. M. rosenbergii were randomly divided into five groups: a control group was fed with basal diet, and four treated groups fed with basal diet supplemented with 0.05%, 0.1%, 0.2%, and 0.4% anthraquinone extract for 8 weeks, respectively. The growth, the variations of haemolymph lysozyme, alkaline phosphatase, nitrogen monoxide, total anti-oxidative capacity, glutathione peroxidase, and malondialdehyde content and the relative level of hepatic HSP70 mRNA were investigated. The growth gain rate, length gain rate, haemolymph alkaline phosphatase activity and the relative level of hepatic HSP70 mRNA of M. rosenbergii fed with 0.1% anthraquinone extract for 6 or 8 weeks were higher than those of the control. Weight gain rate and haemolymph alkaline phosphatase activity of M. rosenbergii fed with 0.2% anthraquinone extract for 8 weeks were higher than those of the control. However feed conversion ratios of M. rosenbergii fed with 0.1% and 0.2% anthraquinone extracts for 8 weeks were lower compared to those of the control ( P < 0.05). The haemolymph lysozyme activity and total anti-oxidative capacity in the group fed with 0.05% anthraquinone extract for 8 weeks were significantly higher than those of the control. However, there were no significant differences in haemolymph nitrogen monoxide concentrations and glutathione peroxidase activities between all treatment groups and the control. The present study suggested that the ingestion of 0.1%–0.2% anthraquinone extracts supplemented with a basal diet had the potential to stimulate immunity, increase the gene expression of HSP70, and promote the growth of prawns.

Growth rates of Chinese and American alligators

Growth rates in two closely related species, Alligator mississippiensis (American alligator) and Alligator sinensis (Chinese alligator), were compared under identical conditions for at least 1 year after hatching. When hatched, Chinese alligators were approximately 2/3 the length and approximately 1/2 the weight of American alligator hatchlings. At the end of 1 year of growth in captivity in heated chambers, the Chinese alligators were approximately 1/2 as long and weighed approximately 1/10 as much as American alligator yearlings. When the animals were maintained at 31 °C, Chinese alligator food consumption and length gain rates dropped to near zero during autumn and winter and body weights decreased slightly, apparently in response to the change in day length. At constant temperature (31 °C), food consumption by American alligators remained high throughout the year. Length gain rates in American alligators decreased slowly as size increased, but were not affected by photoperiod. Daily weight gains in American alligators increased steadily throughout the year. In autumn, provision of artificial light for 18 h a day initially stimulated both length and weight gain in Chinese alligators, but did not affect growth in American alligators. Continuation of the artificial light regimen seemed to cause deleterious effects in the Chinese alligators after several months, however, so that animals exposed to the normal light cycle caught up to and then surpassed the extra-light group in size. Even after removal of the artificial light, it was several months before these extra-light animals reverted to a normal growth pattern. These findings may be of interest to those institutions engaged in captive growth programs intended to provide animals for reintroduction to the wild or to protected habitat.