Effects of microalgal species and concentrations on the feeding and digestive enzyme activities of Calanus sinicus Effects of stocking density and exchanging water frequency on growth and inner quality of Whitmania pigra Effect of light intensity on the growth and digestive enzyme activity of juvenile sea cucumber Apostichopus japonicas under two kinds of culture methods. Changes of digestive enzyme activity of Tegillarca granosa exposed to cadmium and copper Effects of fructo-oligosaccharides on mucosal morphology, digestive enzyme activity, organic acid and Lactobacillus of the gastrointestinal tract of unweaned piglets Effects of three kinds of host plants on development and some digestive enzyme activities of beet armyworm, Spodoptera exigua