Alfredo Hernández-Llamas

TEMA: A software reference to shrimp Litopenaeus vannamei farming practices

Abstract A user‐friendly expert system (TEMA) was developed as a generic reference relating to TEechnological and MAnagement aspects of shrimp Litopenaeus vannamei farming practices. The software provides assistance to confirm, complement or modify the information that users of the expert system have of semi‐intensive and intensive technologies for grow‐out, and management practices for controlling pond water quality, productivity and feeding. Nursery techniques are also considered. Domain knowledge was represented using 433 rules, which constitute the knowledge base of the expert system. Hypertext protocol was employed to present information menus which include the justification of recommendations and conclusions, references from the literature, useful information regarding the specific topic analysed, support for data entry and on‐screen or printed final reports summarizing the consultation. Software facilities use 627 screens, 62 bibliographical references and 12 400 words in hypertext protocol, TEMA h...

Growth potential of wild juvenile Penaeus stylirostris in earthen ponds receiving chemical and organic fertilizers, and pelleted feed

Abstract The growth potential of wild juvenile Penaeus stylirostris was analyzed in experimental trials using chemical and organic fertilizers and pelleted feed in 0·25 ha earthen ponds. Shrimp were stocked at a low density (1·6 ind/m2). After 103 days, final weight ranged from 9·5 to 26·0 g. The significance of differences in growth response was determined using a reparameterization of the von Bertalanffy growth curve. Maximum growth rates observed in the trials ranged from 0·06 to 0·33 g/day, averaging 0·22 g/day. Maximum rates were related to weight by the equation: ( dw dt ) max =0·034w 0·69 r 2 =0·9,P Pelleted feed produced best growth, chemical fertilizers were acceptable, and organic fertilizers gave poor results. The high growth potential of the species stimulates future research in order to adapt a culture technology to the semi-arid conditions of northwest Mexico, where the species is indigenous.

Bioprocessing of common beans in diets for tilapia. In vivo digestibility and antinutritional factors

BACKGROUND Bioprocessing of ingredients by solid-state fermentation is a low-cost technique for preparing diets. It is performed by adding microorganisms such as Rhizopus oligosporus to bean grains, achieving minimal degradation of nutrients and a significant improvement in digestibility. In particular, fermentation induces favorable changes in beans by reducing enzyme inhibitors, such as phytates and tannins. RESULTS Fermentation significantly (P < 0.05) increased the protein content and digestibility of dry matter and protein compared with whole bean grains, and decreased the content of lipids, ash and phytic acid. Hardening did not have a significant (P > 0.05) effect on the chemical content of beans and digestibility of diets. The dehulled bean meal significantly (P < 0.05) increased protein and lipid content and digestibility of dry matter and protein of beans, and decreased fiber, ash and tannin content. The chemical content of beans and digestibility of ingredients compare favorably with those reported by other authors, indicating the benefits of fermentation and dehulling. CONCLUSION We concluded that bean meal obtained from fermentation or dehulling represents a low-cost alternative for diets for tilapia.

Apparent digestibility coefficient of chickpea, maize, high-quality protein maize, and beans diets in juvenile and adult Nile tilapia ( Oreochromis niloticus )

The objective of our study was to assess the apparent digestibility of plant ingredients in diets for juvenile (50 g) and adult (220 g) Nile tilapia (Oreochromis niloticus). Dietary dry matter and protein apparent digestibility coefficients of four plant-derived feedstuffs (chickpea, maize, high-quality maize protein, and beans) were tested. The beans diet had the lowest apparent digestibility coefficient of dry matter (ADCDM) (69.41%), while no significant differences were detected in ADCDM among the other diets; ADCDM was significantly higher in adults compared with juveniles (77.02 vs. 73.76%). Apparent dry matter digestibility coefficient of ingredients (ADCI) was significantly higher in the chickpea (70.48%) and high-quality protein maize (71.09%) ingredients, and lower in the beans (52.79%) ingredient. Apparent dry matter digestibility coefficient of ingredients was significantly higher in juveniles compared with adults (72.56 vs. 56.80%). The protein digestibility of diet (ADCCP) was significantly higher in the reference diet (93.68%), while the lowest corresponded to the maize (87.86%) and beans (87.29%) diets. Significantly lower apparent digestibility coefficient of protein (ADCICP ) was obtained with the high-quality maize protein (59.11%) and maize (49.48%) ingredients, while higher ADCICP was obtained with the chickpea and beans ingredients (71.31 and 63.89%, respectively). The apparent digestibility coefficient of ingredient crude protein ADCICP was significantly higher in juveniles compared with adults (67.35 vs. 53.46). Digestibility is generally higher in juveniles, and we recommend using chickpea as an ingredient in diets for Nile tilapia.