Weight Loss In Fish Research Articles

Evaluating the feasibility of feeding RAS-produced Atlantic salmon (Salmo salar) during the depuration process: effects on fish weight loss and off-flavor remediation

ABSTRACT Depuration is a proven pre-harvest procedure that eliminates off-flavor from Atlantic salmon produced in recirculating aquaculture systems. However, applied research indicates that depurating salmon lose weight while fasting, which reduces farmgate revenue. Low-ration feeding was therefore evaluated as a method to mitigate weight loss while depurating 3–4 kg Atlantic salmon. Salmon implanted with passive-integrated-transponders were weighed, exposed to concentrated geosmin (GSM) and 2-methylisoborneol (MIB), and stocked in eight pre-disinfected partial reuse systems. Feed was either offered for 4 days or withheld entirely (n = 4) during a 6-day depuration period. Salmon from both treatments rapidly eliminated GSM and MIB, but slightly lower levels remained in fish that were fed (P < .05). Fed and fasted salmon lost 0.3 and 1.1% of their initial body weight, respectively (P < .05). Under the conditions of this study, feeding Atlantic salmon during depuration minimized weight loss without negatively impacting off-flavor elimination.

Effectiveness of particle size of selected plant materials as protectants of stored Clarias gariepinus against Dermestes maculatus infestation

The focus of this study was to determine the efficacy of the different particle sizes of the powder of three plant materials, African Nut-meg (Monodora myristica), Black pepper (Piper guineense) and dry bud of Cloves (Eugenia aromatica) in the control of Dermestes maculatus infestation on stored dried African mud catfish, Clarias gariepinus. Each plant material was pulverized, sieved into 0.5 mm and 0.4 mm particle-sizes, rubbed at 5 g of powder onto the body of 55 g dried fish and placed in Kilner jar in triplicates. The weight loss, adult / larvae emergence and adult mortality of treated fish were determined. The results showed that 0.4 mm particle size of the powder of P. guineense and E. aromatica prevented the infestation of D. maculatus as demonstrated by low fish weight loss, low level of adult / larvae emergence and high mean value of adult insect mortality. Higher number of larvae emergence and weight losses were recorded in the fish exposed to 0.5 mm of each plant powder and 0.4 mm of M. myristica. The study revealed that stored catfish could be treated with smooth particle sizes of Piper guineense and Eugenia aromatica, and can significantly serve as protectants of smoked C. gariepinus against Dermestes maculatus infestation.

Nickel-induced oxidative stress and apoptosis in Carassius auratus liver by JNK pathway

Nickel (Ni) is ubiquitous in the biosphere and is a common component of natural fresh waters. When present in high concentrations, it becomes toxic to aquatic organisms. It is known that Ni toxicity may induce oxidative stress and apoptosis. However, the precise mechanism and the pathways that are activated in fish are still unclear. Thus, this study aimed to assess which apoptotic pathways are triggered by Ni in Carassius auratus liver, the main target of waterborne pollutants. Fish were exposed to 10, 25, 50 and 100mg/L of nickel sulfate for 96h. Our data showed that Ni exposure caused fish weight loss (by 10–12%) and decreased locomotory activity (by 1–25%). Ni exposure significantly decreased the relative lymphocyte count (by 1–24%) and increased the relative count of monocytes (by 25–111%) and neutrophils (by 10–322%) as compared to controls. Ni induced oxidative stress, as evidenced by increasing of lipid peroxidation level (29–91%) and depleting of the glutathione levels (7–79%) in fish liver. Ni also suppressed the activities of superoxide dismutase (by 39–55%) and glutathione peroxidase (16–24%) and decreased ATP levels (13–51%) in livers. Moreover, liver caspase-3, one of the key executioners of apoptosis, was markedly activated by the Ni exposure. Ni exposure also increased expression levels of phosphorylated Jun N-terminal kinases (JNK) in liver, which in turn activated pro-apoptotic signaling events by breaking the balance between pro-apoptotic and anti-apoptotic Bcl-2 proteins. In conclusion, these results suggested that Ni induced oxidative stress and apoptosis, at least, via the JNK signaling pathway.

Effect of dietary Ulva and Spirulina on weight loss and body composition of rainbow trout, Oncorhynchus mykiss (Walbaum), during a starvation period

A study was conducted to determine the effect of dietary algal supplementation on weight loss and proximate composition in rainbow trout, Oncorhynchus mykiss, during starvation. An algae-free control diet (C) and four experimental diets, including varying levels of raw Ulva meal (5% = U5; 10% = U10) and Spirulina meal (5% = S5; 10% = S10) were formulated. Fish were fed to satiation for 12 weeks and then subjected to a 3-week starvation period. Body weight, viscerosomatic index (VSI, %), hepatosomatic index (HSI, %), dress-out (DO, %) and chemical composition of carcass were analysed at the end of each starvation week. The accumulated weight loss of the fish fed dietary algae was almost 50% less than the control group (p < 0.05) after 2 and 3 weeks starvation. No significant differences in weight loss were observed among the fish fed different algal diets during the starvation period. Total body protein and ash contents remained constant in all groups throughout the starvation period. Fish in all treatments lost a significant level of total lipids and changes of liver fatty acid profiles were also observed. Results indicate that low level inclusion of algae in aquafeeds may have economical advantages in terms of reducing weight loss in fish when subjected to a short-term fasting period, that sometimes is necessary after a heavy rainfall or when fish stocks are held back to meet market demand.

Study of Fish Weight Loss in Solar Dryer Across Different Agro-Ecological Zones of Nigeria

AbstractDrying sessions were conducted across Nigeria to study the interaction between fish weight loss and the meteorological parameters. Correlation analyses using weight loss values show that latitude is strongly related (r =+0.96) to weight loss of fish inside the dryer while altitude had a weak relationship (r = +0.24) with weight loss. The results show that New Bussa recorded more weight loss of fish than Jos, despite their uniform latitude. Weight loss records in Jos, was however better than those of Warri and Ibadan.

Study of Fish Weight Loss in Solar Dryer Across Different Agro-Ecological Zones of Nigeria

Study of Fish Weight Loss in Solar Dryer Across Different Agro-Ecological Zones of Nigeria

Effect of some pulverised plant materials on the developmental stages of fish beetle, Dermestes maculatus Degeer in smoked catfish (Clarias gariepinus) during storage.

The effectiveness of pulverised plant materials; Tithonium diversifolia, Afromomum melegueta, Nicotiana tabacum, Monodora myristica and Piper guineense as ovicidal, larvicidal and adult deterents of fish beetle (Dermestes maculatus) in smoked catfish (Clarias gariepinus) during storage were evaluated. Leaves of T. diversifolia, N. tabacum and seeds of A. melegueta, M. myristica and P. guineese were dried and pulverised into powder. Adults and larvae of third generation (F3) of D. maculatus were introduced into Kilner jars containing disinfested fish samples. Pulverised plant materials were applied to the surface of the fish samples at 10% (w/w) and monitored for 40 days, while egg hatchability of the insects was monitored for seven days. The result showed that all the plant materials had varying degree of insecticidal activities. Pulverised powder of P. guineense and A. melegueta were the most effective and significantly (P < 0.05) inhibited egg hatchability and adult emergence of D. maculatus in smoked catfish. N. tabacum gave the lowest insecticidal effect on adults, larvae and eggs of D. maculatus. However, the larvae of D. maculatus were not significantly (P > 0.05) affected by the plant materials. The percentage weight loss in fish treated with P. guineense and A. melegueta were minimal compared with the untreated fish sample. The result of this study showed that pulverised plant materials obtained from P. guineense and A. melegueta could be used to deter egg hatchability and adult emergence of D. maculatus in smoked catfish during storage. This could also reduce percentage losses due to insect infestation on smoked fish during storage.

Long-Term Water Quality and Biological Effects of Alum Treatment of Lake Morey, Vermont

ABSTRACT Lake Morey received one hypolimnetic treatment with alum and sodium aluminate in 1986 to reduce the occurrence of algae blooms caused by internal P loading. Thirteen years of post-treatment monitoring have documented a sustained improvement in water quality in the lake. Comparison of pre-treatment (1977–1985) and post-treatment (1986–1998) data indicated that significant improvements occurred in all water quality variables measured, including spring TP (reduced 66%), summer photic zone TP (reduced 68%), summer photic zone Chi a (reduced 61%), summer Secchi disk transparency (increased 79%), late summer hypolimnetic TP (reduced 83%), and late summer hypolimnetic DO (increased 193%). The one-time alum/aluminate treatment of Lake Morey has thus far succeeded in breaking a cycle of sediment P release and re-precipitation that was initiated during an earlier period in the lake's history. Relative weight loss was observed in samples of large yellow perch during the 3 years immediately following the treatment. Yellow perch condition returned to pre-treatment levels by 1991. Toxicity from elevated dissolved aluminum concentrations in the water column during the summer of treatment may have caused the observed weight loss in fish. The benthic macroinvertebrate community in the upper hypolimnion experienced a 90% decline in density during the year immediately following the alum treatment. The benthic community recovered during subsequent years with density and taxa richness generally exceeding pre-treatment values, possibly in response to improved hypolimnetic DO conditions.

Discussion

The effectiveness of pulverised plant materials; Tithonium diversifolia, Afromomum melegueta, Nicotiana tabacum, Monodora myristica and Piper guineense as ovicidal, larvicidal and adult deterents of fish beetle (Dermestes maculatus) in smoked catfish (Clarias gariepinus) during storage were evaluated. Leaves of T. diversifolia, N. tabacum and seeds of A. melegueta, M. myristica and P. guineese were dried and pulverised into powder. Adults and larvae of third generation (F3) of D. maculatus were introduced into Kilner jars containing disinfested fish samples. Pulverised plant materials were applied to the surface of the fish samples at 10% (w/w) and monitored for 40 days, while egg hatchability of the insects was monitored for seven days.The result showed that all the plant materials had varying degree of insecticidal activities. Pulverised powder of P. guineense and A. melegueta were the most effective and significantly (P<0.05) inhibited egg hatchability and adult emergence of D. maculatus in smoked catfish. N. tabacum gave the lowest insecticidal effect on adults, larvae and eggs of D. maculatus. However, the larvae of D. maculatus were not significantly (P>0.05) affected by the plant materials. The percentage weight loss in fish treated with P. guineense and A. melegueta were minimal compared with the untreated fish sample.The result of this study showed that pulverised plant materials obtained from P. guineense and A. melegueta could be used to deter egg hatchability and adult emergence of D. maculatus in smoked catfish during storage. This could also reduce percentage losses due to insect infestation on smoked fish during storage.

養魚飼料のタンパク質源‐ＩＶ ハマチに対する大豆油粕栄養価の加熱時間に伴う変化

In order to elucidate changes in the nutritive value of defatted soybean meal with the duration of heating time, the general and amino acid composition and trypsin inhibitor (TI) activity of several types of meal heated at 108°C for 0-40 min were determined, and the growth, feed conversion, protein digestibility, and body composition of young yellowtail Seriola quinqueradiata were also compared by feeding them with diets containing about 20% of each meal. The nutritive value of raw defatted soybean meal was extremely low: it had a high TI activity and high nitrogen solubility index, resulting in a low protein digestibility; its feeding caused weight loss in fish with inferior hematological characteristics and body composition. The nutritive value of the meal was markedly improved by heating it for 20 min, and was maximized by heating it for 30 min, but it decreased slightly after being heated for 40 min. The heating treatment hardly improved the general and amino acid composition of the soybean meal, while it caused a rapid inactivation of TI together with a marked improvement in protein digestibility, indicating that the improvement of its nutritive value by heating could be mainly attributed to an elimination of heat-labile growth inhibition factors such as TI. Also, the comparison in nutritive value between these heated soybean meals and soy protein concentrates suggests the continuing existence of heat-stable growth inhibition factors in the heated meal.

Comparaison de la croissance et de la composition chimique d' Oreochromis (Tilapia) niloticus L. et de Cichlasoma (Theraps) melanurum Gth. Nourris avec Azolla

The growth of two species of Cichlidae, the African Oreochromis niloticus and the Central American Cichlasoma melanurum, fed with three different diets (100% pellets, 50% pellets and 50% Azolla, 100% Azolla) was compared. The growth performances of O. niloticus ( G=2.3) fed only with pellets were higher than those of C. melanurum ( G=0.9). With the mixed diet (50% pellets and 50% Azolla) growth was reduced for both species but this reduction was proportionally lower with C. melanurum. The fish fed exclusively with Azolla showed negative growth but fish weight loss was least for C. melanurum. Comparison of the chemical composition of the two fish species reveals significant differences. Generally moisture is lower for C. melanurum and lipid concentration is higher for this species with all three diets. Fed with Azolla, both species have a higher moisture and lower lipid concentration. Crude protein concentration (±15%) is very similar for both species regardless of diet. In conclusion, for intensive fish culture based on commercial pellets, the African species O. niloticus performs better than the American C. melanurum. On the other hand, the use of Azolla as feed for these fish does not seem very satisfactory but experiments should be conducted with typical herbivorous Cichlidae which may be able to utilize this fern in agro-piscicultural ecosystems.