A Tribute to Dr. Ronald Hardy for his Contribution to Aquaculture Nutrition.

Ronald William Hardy was born in 1947 in Vancouver, Canada. He comes from a very academically able Canadian/Scottish family. His grandparents came from Scotland and moved to Vancouver in 1909. In his father´s family there were doctors, nurses and also missionaries in Canada near Alaska. Ron´s father worked in agriculture communities around Seattle (an expert in poultry science), and used to take his 6 years old son salmon fishing, that was Ron´s first connection with salmon and trout. His mother came from a family of Scottish farmers, and then scientists; she was a Microbiologist and worked on tuberculosis. Ron took pre-medicine curriculum for 4 years, receiving his BS in Zoology in 1969 at the University of Washington. He took many jobs, including on farms and railroads, to pay for his college education. In 1970 he married Elizabeth the future mother of his daughters (Anna and Clare). Then in 1973, he obtained a M.S. in Animal Sciences/Nutrition at Washington State University; his thesis subject was “Studies on factors in rye which cause growth depression in chicks”. One day at the University Library he found the book of Dr. Halver on fish nutrition and, discovering the important gap in this area with respect to poultry, porcine and bovine nutrition, realized the huge potential of this new activity. Halver´s book was his second inspiration… It was at this time that he commenced his life‟s work on the nutrition of fish, graduating with a PhD in Fisheries at the University of Washington, Seattle (1978). Hardy‟s PhD dissertation subject was “Effects of dietary protein and pyridoxine levels on growth and disease resistance of chinook salmon”, having as mentors Dr. Halver (biochemistry and nutrition) and Dr. Brannon (salmon biology)

Chemical composition of cultivated seaweed ulva clathrata (Roth) C. Agardh

Samples of cultivated Ulva clathrata were collected from a medium scale system (MSS, 1.5 1.5 m tank), or from a large scale system (LSS, 0.8 ha earthen pond). MSS samples were dried directly while the LSS sample was washed in freshwater and pressed before drying. Crude protein content ranged 20–26%, essential amino acids accounting for 32–36% of crude protein. The main analysed monosaccharides were rhamnose (36–40%), uronic acids (27–29%), xylose (10–13%) and glucose (10–16%). Some notable variations between MSS and LSS samples were observed for total dietary fibre (26% vs 41%), saturated fatty acids (31% vs 51%), PUFAS (33% vs 13%), carotenoids (358 vs 169 mg kg1 dw) and for Ca (9 vs 19 g kg1 ), Fe (0.6 vs 4.2 g kg1 ), Cu (44 vs 14 mg kg1 ), Zn (93 vs 17 mg kg1 ) and As (2 vs 9 mg kg1 ). The chemical composition of U. clathrata indicates that it has a good potential for its use in human and animal food

Incorporation of dietary nitrogen from fish meal and pea meal (Pisum sativum) in muscle tissue of Pacific white shrimp (Litopenaeus vannamei) fed low protein compound diets

Stable isotope analyses were applied to explore the relative dietary nitrogen contributions from fish meal and pea meal (Pisum sativum) to muscle tissue of Pacific white shrimp postlarvae (141 ± 31 mg) fed low protein diets having different proportions of both ingredients as the sole dietary protein sources. A negative control diet was formulated to contain 100% pea meal and six more isoproteic diets to have decreasing levels of pea meal-derived nitrogen: 95, 85, 70, 55, 40 and 0 % of the initial level. Growth rates were negatively correlated to dietary pea protein inclusion due to progressive essential amino acid deficiencies (sulfur amino acids, threonine, lysine, histidine). The nitrogen turnover rate significantly increased in muscle tissue of shrimps fed diets having high levels of pea meal; however, contrary to observations from a previous study using soy protein , the relative contributions of dietary nitrogen from pea meal to shrimp muscle tissue were equal or higher than expected contributions established by the dietary formulations. Results highlight the effectiveness of stable isotope analysis in assessing the nutritional contributions of alternative ingredients for aquaculture feeds and the potential suitability of pea as a source of protein (provided the diets are nutritionally balanced)

Digestibility of different wheat products in white shrimp Litopenaeus vannamei juveniles

Dry matter, energy, crude protein and amino acid apparent digestibility coefficients (ADCs) were determined in white shrimp juveniles for six wheat products: hard red winter whole grain meal (HWG), Rayon whole grain meal (RWG), Durum whole grain meal (DWG), hard red winter clear flour (HCF), mixed wheat 2nd clear flour (MCF) and semolina (S). The test diets included 30% of the test ingredients and 70% of a ground commercial diet supplemented with 1% chromic oxide and 1% sodium alginate. Amino acid contents in the ingredients, diets and feces were analyzed, and digestibility was determined by difference in order to minimize the impact of endogenous amino acid losses; crude protein and amino acids ADCswere adjusted for dietary preprandial losses in seawater. In general, nutrients digestibility was far higher in the wheat products than in the fish meal-based reference diet. Drymatter and crude proteinADCswere not statistically different amongwheat products (from84 to 96% and from88 to 107% respectively). Energy ADCs were significantly higher for clear flours (96% for HCF and MCF) than forwhole grainmeals and S (from83 to 86%). Total amino acids (TAA) and essentialamino acids (EAA) ADCs, once adjusted for preprandial leaching fromthe experimental diets, ranged from81 to 89% and from 58 to 81% respectively, and were statistically comparable among wheat products. Low Thr ADCs appear as a common feature of the amino acids digestibility profiles for whole grain meals, clear flours, or semolina

In vitro characterization of the antiviral activity of fucoidan from Cladosiphon okamuranus against Newcastle Disease Virus

Newcastle Disease Virus (NDV) causes a serious infectious disease in birds that results in severe losses in the worldwide poultry industry. Despite vaccination, NDV outbreaks have increased the necessity of alternative prevention and control measures. Several recent studies focused on antiviral compounds obtained from natural resources. Many extracts from marine organisms have been isolated and tested for pharmacological purposes, and their antiviral activity has been demonstrated in vitro and in vivo. Fucoidan is a sulfated polysaccharide present in the cell wall matrix of brown algae that has been demonstrated to inhibit certain enveloped viruses with low toxicity. This study evaluated the potential antiviral activity and the mechanism of action of fucoidan from Cladosiphon okamuranus against NDV in the Vero cell lin

Application of stable isotope analysis to differentiate shrimp extracted by industrial fishing or produced through aquaculture practices.

Carbon and nitrogen stable isotope values were determined in Pacific white shrimp (Litopenaeus vannamei) with the objective of discriminating animals produced through aquaculture practices from those extracted from the wild. Farmed animals were collected at semi-intensive shrimp farms in Mexico and Ecuador. Fisheries-derived shrimps were caught in different fishing areas representing two estuarine systems and four open sea locations in Mexico and Ecuador. Carbon and nitrogen stable isotope values (13CVPDB and 15NAIR) allowed clear differentiation of wild from farmed animals. 13CVPDB and 15NAIR values in shrimps collected in the open sea were isotopically enriched (−16.99‰ and 11.57‰), indicating that these organisms belong to higher trophic levels than farmed animals. 13CVPDB and 15NAIR values of farmed animals (−19.72‰ and 7.85‰, respectively) partially overlapped with values measured in animals collected in estuaries (−18.46‰ and 5.38‰, respectively). Canonical discriminant analysis showed that when used separately and in conjunction, 13CVPDB and I5NAIR values were powerful discriminatory variables and demonstrate the viability of isotopic evaluations to distinguish wild-caught shrimps from aquaculture shrimps. Methodological improvements will define a verification tool to support shrimp traceability protocols

Uso de secuestrantes para disminuir la toxicidad de micotoxinas en alimentos para acuacultura.

La presencia de micotoxinas en alimentos para animales terrestres y acuáticos puede llegar a reducir significativamente el crecimiento, consumo de alimento, sobrevivencia e incrementar la tasa de conversión alimenticia así como causar afeccciones en el sistema inmune, por lo que pueden ser responsables de pérdidas económicas considerables. Para prevenir la contaminación de los ingredientes con micotoxinas durante su cultivo, cosecha y almacenamiento se han utilizado un sin número de procedimientos como buenas prácticas agrícolas, selección de semillas resistentes al ataque de hongos y a la formación de micotoxinas, uso de compuestos químicos durante el almacenamiento, remoción de micotoxinas por procesos físicos, etc., no obstante, en algunas ocasiones no se logra impedir la generación de estas toxinas. La inclusión de remediadores como: secuestrantes, biotransformadores y compuestos protectores son otras alternativas que permiten reducir al máximo la presencia de estas sustancias en los alimentos terminados o disminuir los estragos cuando los animales consumen alimentos contaminados con micotoxinas. En este trabajo se presenta una revisión general del uso de estos productos en alimentos para animales terrestres y acuáticos, incluyendo estudios de su efectividad in vivo así como consideraciones importantes al momento de incluirse en alimentos terminados

La importancia nutricional de la productividad natural en operaciones de pre-cría y engorda de camarón indicada mediante isótopos estables

La productividad natural de los estanques de cultivo semi-intensivo está frecuentemente representada por una gran cantidad de elementos que continuamente aportan nutrientes a los organismos en cultivo. Estos componentes dietarios pueden exhibir firmas isotópicas naturalmente distintas y por lo tanto permiten establecer relaciones entre los organismos consumidores y sus respectivas dietas. Los valores isotópicos pueden medirse e integrarse en modelos simples para cuantificar la contribución relativa de múltiples fuentes nutritivas al crecimiento del organismo consumidor. De esta forma, es posible estimar la contribución dietaria relativa de los diversos elementos presentes ya sea en los ambientes naturales de cultivo o incluidos en dietas y regímenes de alimentación experimentales. Los análisis isotópicos proveen información no solo acerca de la selección, captura e ingestión de material, sino también acerca de las cantidades de nutrientes asimilados en los tejidos del consumidor. El presente documento resume la importancia nutricional que presenta para el camarón algunos de los diversos elementos encontrados en la productividad natural. De la misma forma, se expone una síntesis de los resultados encontrados en estudios en los que se han utilizado valores isotópicos para determinar las contribuciones de diversos elementos nutricionales al crecimiento del camarón en las fases de pre-cría y engorda

Uso de ulva clathrata en la nutrición del camarón blanco: revisión

En los últimos 4 años, el Programa Maricultura a evaluado en camarón blanco la macroalga Ulva clathrata producida por Aonori Aquafarms, Inc. Se ha analizado la composición química de la Ulva producida bajo diferentes condiciones de cultivo. Se ha mostrado que la inclusión de la harina de Ulva en alimentos para camarón resulta en una mejora en la calidad del pellet (mayor estabilidad en el agua, mayor absorción de agua y textura más suave), en el consumo de alimento en la eficiencia alimenticia, en la tasa de crecimiento, y en la calidad del camarón producido (mayor pigmentación). Se ha encontrado que el co-cultivo de Ulva y camarón representa una alternativa sustentable para mejorar la calidad de agua en los estanques, para reducir la necesidad de alimento artificial y para mejorar la calidad del producto. En medio controlado, se ha demostrado que la Ulva fresca tiene “per se” un efecto promotor del crecimiento como alimento natural complementario y este efecto se manifiesta aun en ausencia de producción natural. El efecto del procesamiento del alga y del proceso de manufactura del alimento sobre el factor de crecimiento de Ulva incluida en el alimento también ha sido estudiado. La digestibilidad aparente de la materia seca, proteína, y aminoácidos de la harina de Ulva se ha determinado. Una revisión de estos estudios es presentada en este artículo

Apparent digestibility of dry matter, crude protein, and amino acids of six rendered by-products in juvenile Litopenaeus vannamei

Apparent digestibility coefficients (ADC) of dry matter, crude protein (CP), and amino acids (AA) were evaluated in diets with six rendered by-products used to feed juvenile Pacific white shrimp: two poultry meals (poultry meal 1, 69% CP; poultry meal 2, 72% CP), two feather meals (89% CP), one blood meal (96% CP), and one pork meal (57% CP). Experimental diets were formulated with 30% of the test ingredient and 70% of a commercial diet supplemented with 1% of chromium oxide as inert marker. AA contents in ingredients, diets, leached diets, and feces were determined by high performance liquid chromatography. Preprandial AA losses attributed to leaching were higher in the blood meal diet (15%) and pork meal diet (10%). Poultry meal diets 1 and 2 showed mean AA losses of 3% and 5%, respectively, while the reference diet had a mean AA leaching of 6%. The AA that had the highest leaching rates were lysine (21%), methionine (15%), and histidine (12%). The ADC of dry matter was higher for poultry meals 1 (70%) and 2 (73%), followed by pork meal (69%), feather meals (61%), and blood meal (57%). The digestibility of CP was higher for poultry meals (78–80%), followed by pork meal (76%), and blood meal and feather meals (65–67%). The digestibility of CP in the reference diet (83%) was higher than that observed for all the animal by-product meals except the poultry meals. The ADC of the sum of AA adjusted for nutrient leaching fluctuated from 65% for blood meal to 80% for poultry meals