Six isonitrogenous (390 g kg )1 ) and isoenergetic (16.2 kJ g )1 ) diets with varying carbohydrate : lipid (CHO : L) ratios (202.5-1.74), were fed to triplicate groups of 25 fish in indoor recirculation system. Over 8-week-growth trial, best weight gain (WG), specific growth rate, feed conversion ratio, protein efficiency ratio and protein production value (P < 0.05) were observed in fish-fed diets with CHO : L ratio of 7.5. Fish fed either the lowest (1.7) or highest (202.5) CHO : L ratio tended to produce lower (P < 0.05) growth and feed conversion efficiencies. The values of viscerosomatic index, hepatosomatic index and intraperitoneal fat ratio increased as dietary CHO : L ratios decreased. There were no significant differences in whole body and liver crude protein among dietary treatments. Whole body and liver lipid increased as CHO : L ratios decreased. Plasma cholesterol and triacylglyceride levels increased linearly as dietary CHO : L ratios decreased. Activities of glucokinase and pyruvate kinase were stimulated by elevated levels of dietary carbohydrate; however, activities of lipase (LPS) and alkaline phosphatase were stimulated by elevated levels of dietary lipid. Based on a second-order polynomial regression analysis of WG against dietary carbohydrate and lipid levels, 275 g kg )1 of carbohydrate and 59 g kg )1 of lipid, corresponding to a CHO : L ratio of 4.7, in a diet holding 390 g kg )1 of crude protein and 16.3 kJ g )1 of gross energy, proved to be optimal for grass carp. These results indicated that utilization of dietary lipid and carbohydrate was moderate in grass carp, but the fish were a little more capable of utilizing lipid compared with carbohydrate. KEY WORDS

An 8‐week feeding trial was conducted to determine the quantitative lysine requirement of juvenile grouper Epinephelus coioides (initial mean weight: 15.84 ± 0.23 g, mean ± SD) in eighteen 500‐L indoors flow‐through circular fibreglass tanks provided with sand‐filtered aerated seawater by feeding diets containing six levels of l‐lysine ranging from 19.2 to 39.5 g kg−1 dry diet in 4 g kg−1 increments. The diets, in which 250 g crude protein kg−1 diet came from fish meal and soybean protein concentrate, and 230 g kg−1 from crystalline amino acids, were formulated to simulate the amino acid profile of 480 g kg−1 whole chicken egg protein except for lysine. Each diet was assigned to three tanks in a completely randomized design. Grouper were fed to apparent satiation twice daily during the week and once daily on weekends. Weight gain and specific growth rate increased with increasing levels of dietary lysine up to 27.2 g kg−1 (P < 0.05) and remained nearly the same thereafter (P > 0.05). Feed efficiency was the poorest for fish fed the lowest lysine diet (P < 0.05) and showed no significant differences among other treatments (P > 0.05). Survival could not be related to dietary treatments. Body composition remained relatively constant except for lipid contents in muscle and liver. Total essential amino acid contents in liver increased with dietary lysine level although there was a slight decline for fish fed the highest lysine level of diet. Plasma protein content increased with increasing dietary lysine level (P < 0.05), but cholesterol, triacylglycerol and glucose contents were more variable and could not be related to dietary treatments. Dietary lysine level significantly influenced morphometrical parameters (condition factor, hepatosomatic index and intraperitoneal fat ratio) of juvenile grouper (P > 0.05). Broken‐line analysis of weight gain indicated the dietary lysine requirement of juvenile grouper to be 28.3 g kg−1 diet or 55.6 g kg−1 dietary protein.

Previous studies of the direct actions of bisphosphonates on bone have mainly been limited to their effects on bone-resorbing osteoclasts and little is known about the direct effects of bisphosphonates on osteoblasts. Here we report the direct effects of alendronate on the proliferation and osteogenic differentiation of the MG-63 osteoblast-like cell line. Cell proliferation was determined with the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay, osteogenic differentiation was evaluated with an alkaline phosphatase bioassay and by analysis of gene expression by reverse transcription-polymerase chain reaction, and the extent of calcium deposition was measured using Alizarin Red S staining. Alendronate significantly increased cell numbers over control values, with the greatest effect at 10(-8) M. Alkaline phosphatase activity and gene expression of bone morphogenetic protein 2, type I collagen and osteocalcin were increased after alendronate treatment. Alendronate also stimulated calcium deposition. We conclude that alendronate, apart from inhibiting osteoclastic bone resorption, is also a promoter of osteoblast proliferation and maturation.

This study was conducted to investigate the effect of dietary manganese (Mn) on growth, vertebrae and whole-body Mn content of juvenile grouper, and to examine the effect of dietary Mn on copper (Cu), iron (Fe), zinc (Zn), calcium (Ca), phosphorus (P) and magnesium (Mg) content of vertebrae and whole body. Seven casein-gelatin-based diets were supplemented with 0, 5, 10, 15, 20, 50 and 1000 mg kg )1 of Mn from MnSO 4 AEH 2 O. Grouper with an initial weight of 12.9 ± 0.4 g were fed to satiation with one of the seven diets for 8 weeks. Growth was not significantly affected by dietary Mn supplements. Vertebrae Mn increased from 31.7 to 118.1 mg kg )1 dry weight with dietary Mn supplement increasing from 0 to 50 mg kg )1 (y = )0.0002x 3 + 0.0162x 2 + 1.3903x + 26.27, R 2 = 0.9561, where y is the vertebrae Mn content and x is the dietary Mn content). Whole-body Mn increased from 2.5 to 7.8 mg kg )1 wet weight with dietary Mn supplement increasing from 0 to 50 mg kg )1 (y = 0.00001x 3 ) 0.00107x 2 + 0.11054x + 2.24615, R 2 = 0.9080, where y is the whole-body Mn content and x is the dietary Mn content). Dietary Mn had no significant effect on vertebrae Fe, Ca, P and Mg content, and whole-body Cu, Zn and Mg content. However, vertebrae Zn and whole body Ca, P were highest in fish fed diet supplemented with 15 mg kg )1 of Mn. Based on this, Mn supplement of 15 mg kg )1 might be the optimum when the basal diet contained 4 mg kg )1 of Mn. Fish fed diet supplemented with 1000 mg kg )1 of Mn did not show any gross abnormality or change in feeding behaviour, but Mn contents of vertebrae and whole body were as high as 695.1 mg kg )1 dry weight and 42.5 mg kg )1 wet weight, respectively. Also, whole body Fe decreased significantly when Mn supplement was up to 1000 mg kg )1 . KEY WORDS

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