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Haliotis Rubra (haliotis + rubra)
Selected AbstractsA simple model for the determination of the relative utilization efficiency of protein by blacklip abalone (Haliotis rubra Leach)AQUACULTURE NUTRITION, Issue 1 2010G.A. DUNSTAN Abstract A 6-week growth rate trial of 6.7 mm ± 1.35 SD long blacklip abalone (Haliotis rubra) fed one of four graded protein feeds (26%, 32%, 37%, 45% crude protein, CP) resulted in a maximum average growth rate of 81 ,m day,1 (percentage daily weight gain of 5.2% day,1) with the 45% CP diet. Based on the results, a new, simple, non-destructive method to calculate the relative utilization efficiencies (RUE) of nutrients is presented to estimate the relative contributions of a nutrient to growth, body maintenance and the excess used for energy. Calculations of RUE of protein estimated that at the maximum growth rate, 59% of the CP was responsible for growth, while 31% was used for body maintenance and an excess of 10% was lost and presumably catabolized for energy and carbohydrate anabolism. At the %CP where the highest proportion of CP was used for growth, i.e. the maximum RUE of protein for growth (slightly higher at 62%), 35% was used for body maintenance and only 3% of the excess was lost to energy. [source] Growth and feeding in juvenile triploid and diploid blacklip abalone, Haliotis rubra (Leach, 1814), at two temperaturesAQUACULTURE NUTRITION, Issue 6 2006W. LIU Abstract Growth and feeding of juvenile triploid and diploid blacklip abalone Haliotis rubra (Leach, 1814) were investigated at two temperatures of 17 and 21 °C over a 50-day period. There were no differences in growth between triploid and diploid abalone as measured by shell length and body weight. Both triploid and diploid abalone increased in length but not in weight at 21 °C. Condition indices were similar for triploid abalone maintained at both temperatures; however, those for diploid abalone were significantly higher at 17 °C than at 21 °C. Food intake was significantly greater yet feed conversion efficiency was significantly lower in triploid than in diploid abalone. Both the feeding variables were independent of temperature. On average, diploid abalone were able to convert 1 g of dry food ingested to 0.58 g of body weight, but triploid abalone only 0.44 g. [source] Testing options for the commercialization of abalone selective breeding using bioeconomic simulation modellingAQUACULTURE RESEARCH, Issue 9 2010Nick Robinson Abstract The genetic response and economic benefit from alternative breeding programme designs for blacklip and greenlip abalone (Haliotis rubra and Haliotis laevigata, respectively) were evaluated using a computer simulation model. Two selection criteria were investigated, one used family breeding values for liability to disease challenge test infection and the other used a direct selection of the best performing individuals across families for growth rate. Five scales of breeding programme were tested and the model predicted that if growth rate is the only selection criterion, breeding programmes of a scale using 150 families of each species each generation would result in 12,13% genetic improvement in initial generations and have the greatest beneficial economic impact on the Australian abalone industry of the options tested. The model predicts an average discounted benefit,cost ratio of 48:1, total added discounted benefit of AU$4.90 for each kilogram of abalone produced and nominal economic effect on operating income of over AU$16 million per year after 10 years. If disease resistance is the only selective breeding criterion, 100 families of each species would result in the highest benefit,cost ratio of the options tested, although some genetic gain would need to be sacrificed to reduce inbreeding to acceptable levels in this scenario. A strategy for a stand-alone abalone selective breeding cooperative was also modelled. For a farm of current tank area yielding 100 t year,1, participation is expected to yield over AU$0.7 million in discounted total added production value and annual discounted returns of over AU$0.4 million per annum by year 10. [source] Effects of water flow rate on growth rate, mortality and biomass return of abalone in slab tanksAQUACULTURE RESEARCH, Issue 6 2010Matthew Wassnig Abstract The capital-intensive nature of land-based abalone farming demands that infrastructure be fully utilized. This study investigated whether the negative impact of high stocking density in shallow raceway tanks could be ameliorated by optimizing water flow. We quantified the effect of flow rate (87,246 L min,1) on the performance of 2-year-old hybrid abalone (Haliotis laevigata and Haliotis rubra) held at two stocking densities (11400 and 7600 tank,1). A 50% higher density yielded a 27% increase in biomass gain, despite a 10% growth reduction and 3% higher mortality. At the lower density, there was an optimal flow rate of approximately 200 L,1, at which biomass gain was 474 kg and the feed conversion ratio (FCR) was 1.31. At the higher density, biomass gain (max = 658 kg) and FCR (min = 1.41) improved linearly with increasing flow, suggesting that an optimal flow rate exists at 246 L,1 or beyond those tested. Increased oxygen availability with increasing flow is thought to have enhanced abalone performance, although flows greater than 200 L min,1 may have reduced performance at low density due to feed washout and nutrient leaching. Overall, greater financial return per tank was favoured by the combination of high stocking density and high water flow. [source] Effects of density and food ration on the growth rate, mortality and biomass return of abalone in slab tanksAQUACULTURE RESEARCH, Issue 13 2009Matthew Wassnig Abstract We determined how varying stocking density and food ration can influence the growth, mortality and biomass return of abalone raised in slab tanks. The abalone used were 2- year-old hybrids of Haliotis laevigata and Haliotis rubra. The experimental design involved replicate tanks and three levels of each factor (normal practice and ±20% density or food ration). Although increasing density from that typically used in farm practices reduced the growth rate by roughly 6%, biomass return increased by 15.5%, over the 9-month period. Increasing feed ration by 20% boosted biomass by significantly increasing abalone growth during the first 3 months by 4%, but was less effective as the animals grew. Growth, mortality and food conversion ratios were optimized in tanks with a low density and a low feed ration, but economic gains were dominated by the increased biomass return from tanks with a higher stocking density. It is thought that reduced dissolved oxygen and differing access to food contributed to the patterns observed. [source] Growth and reproductive performance of triploid and diploid blacklip abalone, Haliotis rubra (Leach, 1814)AQUACULTURE RESEARCH, Issue 2 2009Wenshan Liu Abstract Growth and reproduction of triploid and diploid blacklip abalone Haliotis rubra (Leach, 1814) were compared in a 30-month study. Triploidy was induced by inhibition of the second polar body formation using 6-dimethylaminopurine (6-DMAP) or cytochalasin B (CB). There were no significant differences in growth and survivorship between triploid and diploid abalone. However, triploid abalone had a more elongated shell and greater foot muscles than diploid abalone. A slightly curvilinear growth in shell length was conformed to all treatments. While diploid abalone had reached sexual maturity and spawned during the study, gonadal development and gamete maturation were abnormal in triploids. Female triploids lacked an apparent gonad at the macroscopic level but microscopic examination revealed that they had a thin layer of oogonia development. In contrast, male triploids were able to form similar-sized gonads to diploids during most of the reproductive period, but with brown-yellow discolouration and stalled gametogenesis at spermatocyte formation. Sex ratio of triploid abalone did not deviate from 1:1. With the onset of sexual maturation, growth and gonadal maturation occurred concurrently in diploid abalone, and there was no indication that growth of (diploid) abalone was reduced. [source] Effects of air exposure on the lysosomal membrane stability of haemocytes in blacklip abalone, Haliotis rubra (Leach)AQUACULTURE RESEARCH, Issue 3 2007Liang Song Abstract The neutral red retention (NRR) assay was used to evaluate the effects of air exposure on lysosomal membrane integrity in the haemolymph of blacklip abalone, Haliotis rubra, and its subsequent recovery in water. After acclimation in 16°C water for 7 days, abalone were exposed to an air temperature of 7, 16 or 23°C for 12 h in the air exposure experiment or to these three air temperatures, e.g., for 12, 24 or 36 h, followed by re-immersion in 16°C water in the lysosomal membrane stability recovery experiment. Statistical analyses of the air exposure experiment showed that when abalone were exposed to different air temperatures (7, 16 or 23°C), the lysosomal membrane stability was significantly affected by the air temperature, the exposure duration and their interaction. Air temperature similar to the acclimation temperature had a significantly lower impact on the lysosomal membrane stability within the initial 4.5 h in comparison with the other two temperatures in the same period. The lysosomal membrane stability recovery experiment showed that after air exposure durations of 12, 24 or 36 h, the re-stabilization of the lysosomal membrane was faster in the animals exposed to lower temperatures than those exposed to higher temperatures. The recovery of the lysosomal membrane stability in abalone exposed to lower 7°C air temperature was not significantly affected (F2, 66=0.251, P=0.779) by the exposure durations (12, 24 and 36 h) used in this study. Alternatively, the lysosomal membrane stability in abalone exposed to higher air temperatures of 16 or 23°C recovered at a faster rate when subjected to shorter durations of air exposure (F2, 66=3.663, P=0.031 and F1, 44=17.057, P<0.001 for 16 and 23°C respectively). [source] Pharmacological and histological assessment of gut muscle movement in blacklip abalone, Haliotis rubra (Leach)AQUACULTURE RESEARCH, Issue 5 2003S Edwards We examined the basic pharmacology of abalone gut tissues for adrenergic and peptide receptors using ligand binding and by determining the pharmacological effectors of abalone gut motility in a number of gut regions. Contractile responses could not be elicited, even though we could show the existence of ,-adrenergic and peptide receptors. Responses to any muscle contractile agents, including carbachol and potassium chloride, could not be found in blacklip abalone, Haliotis rubra (Leach). Histology confirmed the relative absence of muscular layers in all the tissues of the gut, indicating that previous literature reports of muscular involvement in contractile movement of gut contents did not appear to apply to this species. [source] | ||||||||||