title: Digestive enzymatic activity on tropical gar (Atractosteus tropicus) larvae fed different diets.
abstract: Digestive enzymatic activity and growth performance on tropical gar (Atractosteus                         tropicus) larvae fed Artemia nauplii (LF), frozen adult Artemia (AB), an artificial diet (AF) with 46% protein and 16% lipids and a starvation group (SG) from first feeding (5 days after hatching-5 DAH) to 34 DAH were studied. All larvae under starvation (SG) died at 15 DAH. By the end of the experimental period, morphological variables (total length, wet weight and specific growth rate) were significant in larvae fed AF compared to LF and AB. All enzymes studied in the experiment were present since the start of exogenous feeding (including pepsin) and the enzymatic activity varied with the diets. Low levels of enzymatic activity were observed until the 29 DAH; however, after this moment, there was a significant increase (eightfold), particularly for the AF treatment. In vitro protein digestibility tests performed with enzymatic extracts showed that artificial diets with 52% protein and 14% lipids were better digested by larvae before 30 DAH, while diets with 45% protein and 11% lipids were better digested after this age. Taking into account the better growth performance, higher enzymatic activity and better protein digestibility obtained, artificial diets can be used since the start of exogenous feeding on tropical gar larvae, as in other lepisosteids.
authors.affiliation: Laboratorio de Ecofisiología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza, NL, Mexico.
authors.forename: Carlos
authors.initials: C
authors.lastname: Aguilera
authors.forename: Roberto
authors.initials: R
authors.lastname: Mendoza
authors.forename: Israel
authors.initials: I
authors.lastname: Iracheta
authors.forename: Gabriel
authors.initials: G
authors.lastname: Marquez
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000378:metabolism; D000626:Aminopeptidases / Q000378:metabolism; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001156:Artemia; D002918:Chymotrypsin / Q000378:metabolism; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage / Q000378:metabolism; D004063:Digestion / Q000502:physiology; D004064:Digestive System / Q000201:enzymology; D029941:Fish Proteins / Q000378:metabolism; D005399:Fishes / Q000254:growth & development / Q000378:metabolism*; D007814:Larva / Q000201:enzymology / Q000254:growth & development; D008049:Lipase / Q000378:metabolism; D010434:Pepsin A / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D013217:Starvation / Q000201:enzymology; D014357:Trypsin / Q000378:metabolism
chemical_list: D004044:Dietary Proteins; D029941:Fish Proteins; D008049:Lipase; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D010447:Peptide Hydrolases; D000626:Aminopeptidases; D002918:Chymotrypsin; D014357:Trypsin; D010434:Pepsin A