scholarly journals Technical feed quality influences health, digestion patterns, body mineralization and bone development in farming of the stomachless cleaner fish ballan wrasse (Labrus bergylta)

2021 ◽  
Vol 274 ◽  
pp. 114830
Author(s):  
K. Kousoulaki ◽  
E. Grøtan ◽  
T.M. Kortner ◽  
G.M. Berge ◽  
G. Haustveit ◽  
...  
Author(s):  
Miguel Henriques ◽  
Vitor C. Almada

Underwater behavioural observations were conducted to evaluate the relative importance of cleaning behaviour in three species of common north-eastern Atlantic wrasse (Teleostei: Labridae). At the study site, the only cleaner was Centrolabrus exoletus. A total of 12 species was cleaned, with the wrasse, Symphodus melops and Labrus bergylta being the species most frequently cleaned. Neither S. melops nor Ctenolabrus rupestris, known to be cleaners in other sites or in captivity, could be observed cleaning other fishes. Centrolabrus exoletus was found to be a facultative cleaner fish with cleaning acts representing only 7% of the observed feeding acts. In focal observations of host fishes, the incidence of cleaning acts reached a level (11 h-1 per host) similar to that reported for tropical reef fishes and probably reflects the high numbers of cleaners available. Some factors that may affect the origin of the cleaning interactions are discussed.


2018 ◽  
Vol 183 (12) ◽  
pp. 383-383 ◽  
Author(s):  
Adam J Brooker ◽  
Athina Papadopoulou ◽  
Carolina Gutierrez ◽  
Sonia Rey ◽  
Andrew Davie ◽  
...  

Currently, cleaner fish are one of the most widely used sea lice control strategies in Atlantic salmon aquaculture. Two species are currently being farmed in North Atlantic countries, ballan wrasse (Labrus bergylta) and lumpfish (Cyclopterus lumpus), and the sector in most countries is rapidly expanding towards self-sufficiency. The species are very different both in terms of their biology and life histories and, consequently, production and husbandry methods must be tailored to each species. There are numerous health challenges currently experienced in both species, with bacterial and parasitic diseases being the most prevalent, and cohabitation with salmon may increase the risk of disease. Good husbandry and routine health monitoring are essential, although treatment is often required when disease outbreaks occur. Ballan wrasse and lumpfish are both proven to be effective salmon delousers, although delousing efficacy can be variable in farmed fish; the provision of suitable habitat and acclimation to net-pen conditions may encourage natural behaviours, including delousing, and the use of operational welfare indicators can highlight potential welfare issues. Cleaner fish research is progressing rapidly, although much of the basic knowledge regarding the species’ biology remains unknown. The simultaneous domestication of two new marine aquaculture species is a significant challenge demanding sustained effort and funding over a prolonged period of time. Research must focus on enhancing the robustness of the farmed stocks and increasing hatchery outputs to meet the urgent demands from the salmon sector and protect wild stocks from overfishing.


2019 ◽  
Vol 136 (2) ◽  
pp. 133-146 ◽  
Author(s):  
J McMurtrie ◽  
DW Verner-Jeffreys ◽  
T Cochrane-Dyet ◽  
P White ◽  
R van Aerle ◽  
...  

2020 ◽  
Vol 139 ◽  
pp. 93-102 ◽  
Author(s):  
MF Van Bressem ◽  
P Duignan ◽  
JA Raga ◽  
K Van Waerebeek ◽  
N Fraijia-Fernández ◽  
...  

Crassicauda spp. (Nematoda) infest the cranial sinuses of several odontocetes, causing diagnostic trabecular osteolytic lesions. We examined skulls of 77 Indian Ocean humpback dolphins Sousa plumbea and 69 Indo-Pacific bottlenose dolphins Tursiops aduncus, caught in bather-protecting nets off KwaZulu-Natal (KZN) from 1970-2017, and skulls of 6 S. plumbea stranded along the southern Cape coast in South Africa from 1963-2002. Prevalence of cranial crassicaudiasis was evaluated according to sex and cranial maturity. Overall, prevalence in S. plumbea and T. aduncus taken off KZN was 13 and 31.9%, respectively. Parasitosis variably affected 1 or more cranial bones (frontal, pterygoid, maxillary and sphenoid). No significant difference was found by gender for either species, allowing sexes to be pooled. However, there was a significant difference in lesion prevalence by age, with immature T. aduncus 4.6 times more likely affected than adults, while for S. plumbea, the difference was 6.5-fold. As severe osteolytic lesions are unlikely to heal without trace, we propose that infection is more likely to have a fatal outcome for immature dolphins, possibly because of incomplete bone development, lower immune competence in clearing parasites or an over-exuberant inflammatory response in concert with parasitic enzymatic erosion. Cranial osteolysis was not observed in mature males (18 S. plumbea, 21 T. aduncus), suggesting potential cohort-linked immune-mediated resistance to infestation. Crassicauda spp. may play a role in the natural mortality of S. plumbea and T. aduncus, but the pathogenesis and population level impact remain unknown.


2016 ◽  
Vol 6 (1) ◽  
pp. 846-852
Author(s):  
Olugbenga Adeniran Ogunwole ◽  
B. C Majekodunmi ◽  
R. A Faboyede ◽  
D. Ogunsiji

Effects of supplemental dietary lysine and methionine in a Groundnut Cake (GNC) based diets on meat and bone characteristics of broiler chickens were investigated. In a completely randomized design, a total of 168 one - day – old Arbor acre broiler chicks were randomly allocated to seven dietary treatments each in triplicate of eight birds per replicate. The Seven starter and finishers’ diets were: GNC based diets without any amino acid (lysine or methionine) supplementation (T1); GNC diet + 0.2% lysine (T2); GNC diet + 0.4% lysine (T3); GNC diet + 0.2% methionine (T4); GNC diet + 0.4% methionine (T5); GNC diet + 0.2 lysine and 0.2% methionine (T6) and GNC diet + 0.4% lysine and 0.4% methionine (T7). Experimental diets and water were offered to birds ad libitum in an experiment lasting six-week. At day 42, two birds per replicate were slaughtered, meat and bone characteristics determined. There were significant variations (P<0.05) in the crude protein (%) and ether extract (%), pH1 and pH2 of meat. Thiobarbituric acid reactive substances composition of meat at days 0, 5, and 10 were similar (P<0.05) and were not affected by dietary amino acid supplementation. Tibiotarsal index (mg/mm) of bone (22.10, 27.25, 33.35, 31.40, 28.70, 31.45 and 29.75 for broilers on T1, T2, T3, T4, T5, T6 and T7, respectively) were increased significantly (P<0.05) by amino acid supplementation. Significantly differences (P<0.05) were observed in the calcium, phosphorus and potassium (%) contents of broilers’ bone across treatments. Supplemental lysine and both lysine and methionine improved meat quality and bone development of broiler chickens in this study.


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