Behavioural responses to visual environment in early stage Atlantic cod Gadus morhua L. larvae

Marine fish larvae exhibit species‐specific sensitivity to light, which changes during ontogeny. Our aim was to explore how visual environment, characterized by light intensity, microalgae addition and wall colour, affects spatial distribution of Atlantic cod larvae. We applied two different small‐scale factorial designs, each of them as a series of independent short‐term trials at fixed larval ages from 5 to 35 days post hatch (DPH). Positive phototaxis increased in larvae from 5 to ≈24 DPH, followed by reduced response at later ages. Effects from the experimental factors on larval behaviour changed with age, and significant interactions between factors were present. Algae significantly affected larvae only at 5 DPH, increasing phototactic response. White wall colour induced distribution of larvae close to the tank walls at all ages. The experimental approach demonstrated clear effects from visual environment on larval distribution, and revealed both relative importance of individual factors, interactive effects and temporal changes due to larval ontogeny. Our results suggest that by fine‐tuning the visual environment in tanks, the larval distribution may be managed to improve overall rearing conditions through a more even distribution with reduced closeness to tank walls.     

The influence of salinity on the morphological development of yolk sac larvae of Atlantic halibut, Hippoglossus hippoglossus (L.)

The effects of incubation salinity on survival and morphological development of yolk sac larvae of Atlantic halibut, Hippoglossus hippoglossus (L.), were studied at two salinities, 35.5%o and 32.3%o. Yolk sac larvae incubated at 35.5%o developed early tail deformities before 50 day-degrees (9 days post-hatch), and necrosis, oedema and calculus in the urinary bladder at about 150 day-degrees (28 days post-hatch). However, the incidence and severity of mouth deformity was not influenced by salinity. The cumulative mortality up to first feeding was 17% when the larvae were incubated at 3 5.5%o compared to 7% at 32.3%o. A broad variation between the different larval groups was noted in the extent of injuries induced by the higher salinity. Therefore, salinity must be considered as a critical environmental parameter for the yolk sac larvae of Atlantic halibut in aquaculture.     

Determination of Chemical Composition and Nutritive Value with Fatty Acid Compositions of African Mangosteen (<Emphasis Type="Italic">Garcinia Livingstonei</Emphasis>)

African mangosteen (Garcinia livingstonei T. Anderson) is native to Africa and is exotic to other parts of the world. It is a fruit bearing tree with multiple uses. This study was purposed to determine, by analysis, the chemical compositions and nutritive value of the fruits of African mangosteen. Proximate compositions varied with the portions such as epicarp, mesocarp, endocarp and seed tested. All fruit portions contained carbohydrate (37.67–95.02%) and crude protein (0.65–31.76%) as their major components. Moisture (0.45–3.42%), crude fat (1.23–19.55%), crude fiber (2.93–21.13%) and ash (1.76–5.44%) were also found at different levels, depending upon the portions. All portions of fruit were rich in macro and micro elements. The fruits also possessed phenolics (174.02–10.725?mg GAE per g), flavonoid (19.25 to 99.98?µg QE per g) and alkaloid (1.56 to 9.49?mg/kg) contents. The constitution of tannins and oxalate which contribute towards the anti-nutritive value was also low, thus making the fruits beneficial for consumption. Quality attributes like relative amount of oleic acid, total unsaturated fatty acid, acid value, free fatty acid, peroxide value and iodine value showed that the seed oil of African mangosteen can become one among the oleic acid based vegetable oils for consumption.     

Estimation of Dry Matter Intake by Grazing Comisana Ewes

Veterinary Research Communications -     

Genetic structure of milk protein polymorphisms and effects on milk production traits in a local dairy cattle

The milk protein genetic structure of the Reggiana dairy local cattle with remarkable milk quality properties was analysed and compared with the structure of Italian Friesian and Italian Brown cattle. A total of 1138 individual milk samples from the three breeds were typed by isoelectrofocusing. Polymorphism was found at the α_s1‐casein (CSN1S1), β‐casein (CSN2), κ‐casein (CSN3), and β‐lactoglobulin (LGB) loci. High frequencies were observed for some casein alleles in Reggiana (CSN1S1*C, 25%; CSN2*B: 28%) with considerable differences to those observed in a survey carried out 30 years before. A great variation among breeds was observed for casein haplotype frequencies and high linkage disequilibrium was detected at the three polymorphic casein loci CSN1S1‐CSN2‐CSN3. The prevalent haplotypes were CA²B (23%; Reggiana), BA²A (48%; Italian Friesian) and BA²B (51%; Italian Brown). Higher G_ST values between breeds were observed when haplotype frequencies were considered instead of gene frequencies. In the Reggiana cattle, the occurrence of two casein alleles at a rather high frequency (CSN1S1*C, CSN2*B) allowed to estimate the effects of rare casein haplotypes on milk traits. The CA²B haplotype was associated with a significantly higher milk protein and fat content and a significantly higher protein per cent was found also for the BA¹B haplotype.     

Suitable methods for cryopreservation of semen from Atlantic halibut, Hippoglossus hippoglossus L.

Decrease in the quality and quantity of Atlantic halibut, Hippoglossus hippoglossus L., semen towards the end of the reproductive season hampers production of good-quality embryos. Therefore, cryopreservation of spermatozoa is a method showing potential to facilitate controlled reproduction in Atlantic halibut. The present study aimed at establishing the appropriate cryopreservation procedure. We tested 20 extenders composed of four various diluents and five cryoprotectants (DMSO, DMA, methanol, propylene glycol, and glycerol) to determine the best extender. Then, we examined cryopreservation quality using various methods of loading and various volumes of cryopreserved samples. In most of the tested variants, sperm diluted with an extender showed high motility after 24-h incubation despite the high osmotic pressure of the extender. Modified turbot extender (MTE) was the best of the tested diluents, securing the highest post-thaw motility (P < 0.05), and DMSO, DMA, and methanol were the best cryoprotectants (P < 0.05). There was no significant effect of 15-min equilibration of semen in MTE-based extenders prior to freezing on post-thaw motility (P > 0.05). MTE-based extender was chosen as the most suitable. Semen cryopreserved in straws, Eppendorfs or Ziploc bags in volumes ranging from 0.25 to 20 ml showed similar high fertilization ability. Survival of larvae produced with the cryopreserved sperm did not differ from controls produced with freshly collected sperm. Motility 3 h after thawing was high but depended on the type of cryoprotectant and the volume of cryopreserved sperm (P < 0.05). The developed cryopreservation procedure has been applied at our Atlantic halibut breeding station for seed production.     

Clues to the genesis of a discontinuously distributed fragipan in the northern Apennines,Italy

At about 1000 m above sea level in the Vallombrosa Forest, northern Apennines, Central Italy, a dense pan that meets the diagnostic criteria for fragipans is discontinuously distributed. The unusual slope-parallel “digitate” distribution of the pan suggests that it could have formed on water-saturated soil material that moved as earthflows. Actually, several soils in the Vallombrosa Forest have buried or truncated horizons, indicating episodes of mass movement and deposition. However, the fragipan under study shows a homogeneous morphology throughout, hence not providing clues about the occurrence of episodes that have contributed to the emplacement of the parent material. Also, the physical, chemical, and mineralogical analyses of the fragipan do not reveal discontinuities that help to resolve distinct episodes of deposition. Nevertheless, discontinuities in features such as the degree of alteration of biotite grains and the amount of plasma, seen through the micromorphological investigation at 50–60 cm of the current depth, suggest the occurrence of at least two depositional events. Radiocarbon dating of large-size pieces of charcoal collected at three depths within the fragipan yielded three ages that may reflect different times of accumulation of the parent material during the last glacial period. Post-depositional micromorphological features, such as relatively undamaged clay coatings and a weak platy structure, indicate pedogenesis with the absence of intense pedoturbation.     

Physiological responses associated to substrate water availability of Rosa ‘Eurored’ plants grown in soilless greenhouse conditions

The aim of the present study was to provide a better insight into the adaptive processes to water deficit of Rosa hybrid plants grown in soilless cultivation. Rose plants were grown in a greenhouse under two water regimes, corresponding to 100% and 67% of the irrigation needs. Watering was stopped for 0, 72, and 96 h (dry-down period) and photosynthetic parameters, water relations, chlorophyll fluorescence, carbohydrate and ion content were determined.     

An Intensive Approach to Atlantic Halibut Fry Production

The larval stage is regarded to be the main bottleneck of halibut production. Halibut eggs were obtained from captive broodstock both by stripping and by natural spawning. Artificial photoperiods were used to increase the total spawning season. Yolk sac larvae are presently produced either in small stagnant units or in large flow through systems. A major consideration is to avoid stress of the larvae, caused by mechanical disturbances of the larvae and by high bacterial load or high ammonia levels in the water.
The experiments showed that halibut larvae began to ingest algae earlier than rotifers Brachionus sp. Supplementation of algae to first feeding tanks resulted in enhanced survival and growth rate of the larvae. Both rotifers and Artemia can be enriched with very high levels of highly unsaturated n-3 fatty acids (n-3 HUFA). Enriched live feed, containing high levels of n-3 HUFA and total lipids, enhanced both survival and growth of the halibut larvae. The highest growth rates were obtained with wild zooplankton and addition of algae, but enriched cultivated feed combined with algae resulted in growth of the same magnitude as with wild zooplankton.