Continuous movement behavior of humpback whales during the breeding season in the southwest Indian Ocean: on the road again!

Background: Humpback whales are known to undertake long-distance migration between feeding and breeding sites, but their movement behavior within their breeding range is still poorly known. Satellite telemetry was used to investigate movement of humpback whales during the breeding season and provide further understanding of the breeding ecology and sub-population connectivity within the southwest Indian Ocean (SWIO). Implantable Argos satellite tags were deployed on 15 whales (7 males and 6 females) during the peak of the breeding season in Reunion Island.

Linking pollutant exposure of humpback whales breeding in the Indian Ocean to their feeding habits and feeding areas off Antarctica.

Humpback whales, Megaptera novaeangliae, breeding off la Reunion Island (Indian Ocean) undergo large-scale seasonal migrations between summer feeding grounds near Antarctica and their reproductive winter grounds in the Indian Ocean. The main scope of the current study was to investigate chemical exposure of humpback whales breeding in the Indian Ocean by providing the first published data on this breeding stock concerning persistent organic pollutants (POPs), namely polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), DDT and its metabolites (DDTs), chlordane compounds (CHLs), polybrominated diphenyl ethers (PBDEs), and methoxylated PBDEs (MeO-PBDEs). Analyses of stable isotopes δC and δN in skin resulted in further insight in their feeding ecology, which was in agreement with a diet focused mainly on low trophic level prey species, such as krill from Antarctica.

Contrasted accumulation patterns of persistent organic pollutants and mercury in sympatric tropical dolphins from the south-western Indian Ocean.

Due to their high trophic position and long life span, small cetaceans are considered as suitable bioindicators to monitor the presence of contaminants in marine ecosystems. Here, we document the contamination with persistent organic pollutants (POPs) and total mercury (T-Hg) of spinner (Stenella longirostris, n =21) and Indo-Pacific bottlenose dolphins (Tursiops aduncus, n=32) sampled from the coastal waters of La Réunion (south-western Indian Ocean). In addition, seven co-occurring teleost fish species were sampled and analyzed as well.

A radioimmunoassay of chicken growth hormone using growth hormone produced by recombinant DNA technology: validation and observations of plasma hormone variations in genetically fat and lean chickens.

A radioimmunoassay (RIA) of chicken growth hormone (c-GH) has been developed using growth hormone produced by recombinant DNA technology. The best rabbit antiserum was used at 1/300,000 final dilution. Hormone labelling by iodine-125, achieved by chloramine T, allowed a specific activity of 3.

Performance of layers reared and/or kept under different 6-hour light-dark cycles.

Using 60 hens reared and kept on a standard lighting programme (decreasing followed by increasing photoperiod to 22 weeks of age and 14 h continuous light: 10 h continuous dark during lay) as control, the effects of the following intermittent patterns on development and performance were studied. Group 1. The same rearing programme, followed by, between 20 and 36 weeks, 3 h light (L):3 h dark (D) intermittent and then from 36 weeks a regime in which each light period was progressively shortened by 30 min every 8 weeks with corresponding lengthening of the dark period so that the last cycle used between 52 and 60 weeks was 1.

Activities of amylase, trypsin and lipase in the pancreas and small intestine of the laying hen during egg formation.

1. During a cycle of 14 h artificial light and 10 h darkness, dry matter and enzyme concentrations were measured in the pancreas and gut of egg-forming hens. 2.

Transport of electrolytes and water in the upper jejunum of the fowl in vivo perfusion.

The mechanism(s) of electrolytes (JNa, JC1, JCa and JK) and water transport (JV) were studied in the upper jejunum of the laying hen by an in vivo perfusion procedure. Water secretion is modified by the difference of osmotic pressure between the lumen and plasma and we have estimated the osmotic permeability coefficient (P osm = 17.4 microliter x h-1 x mosm-1 x g-1 DW) and the reflexion coefficient (0.

Effects of an intermittent lighting schedule on the time of egg-laying and the levels of luteinizing hormone, progesterone and corticosterone in the plasma of the domestic hen.

The use of a complex lighting schedule consisting of five blocks of light and five alternating periods of darkness every 24 h completely abolished the normal pattern of egg-laying characteristic of the domestic hen. Animals tended to lay continuously and not in clutch sequences. Ovipositions were not restricted to an 8- to 10-h period of the day, instead they occurred at any time of the solar day with slightly more occurring during the hours of darkness.

Food intake and oviposition by domestic fowl under symmetric skeleton photoperiods.

1. Under a symmetric skeleton photoperiod of 2 h light, 10 h dark, 2 h light and 10 h dark (2L : 10D : 2L : 10D), most ovipositions occurred in the first 10-h dark period with an important mode during the first hour of darkness. 2.

[An hypothesis of the pathogenesis of diarrhoea in the rabbit based on a study of intestinal contents].

Experimental diarrhoea was induced in young rabbits by inoculation with Eimeria intestinalis and E. flavescens. The mineral composition of the intestinal contents was studied and compared to those of control animals.

Jejunal calcium permeability in laying hens during egg formation.

The permeability of the upper jejunum to water, calcium, potassium, sodium and chloride was measured in the immature pullet and then in the laying hen before and during egg-shell calcification by an in vivo perfusion procedure. Jejunal calcium permeability was constant throughout egg formation. Thus, the increase of net absorption during shell calcification was not due to enhanced mucosal capacity for calcium translocation, but rather to a better solubilization of calcium carbonate in the upper digestive tract.

Studies on the avian shell gland during egg formation: the effect of acetazolamide on the transfer of ions to the albumen.

Twenty-five laying hens were fed on a diet containing 100 mg acetazolamide/kg in order to determine the effects of a decrease in the activity of carbonic anhydrase on the transfer of minerals to the egg albumen. Treatment with acetazolamide decreased the rate of shell formation by 44%; reduced the concentrations of water and Na+ in the albumen at the beginning of the plumping stage but increased the accumulation of water during plumping; increased the concentration of Cl- in the albumen after the 6-h stage without any appreciable change in K+ and Ca2+ concentrations. The computed relationships between the concentrations of different ions also showed that the transfer of water and Na+ were linked during egg formation, that a water-independent, acetazolamide-sensitive reabsorption of Na+ occurred after the 10-h stage and that Na+ and Cl- moved simultaneously up to 14 h but with the ratio of Cl- to Na+ three times higher in the treated group.

Studies on the avian shell gland during egg formation: the effect of acetazolamide on the composition of the mucosa.

The effect of acetazolamide, an inhibitor of carbonic anhydrase activity, on the intracellular composition of the shell gland mucosa was determined. The normal cyclic hydration of the mucosal cells was found to be reduced when the egg was in the uterus and the partition of the water between the intra- and extracellular compartments was modified. Acetazolamide decreased the accumulation of Na+ within the cells, inhibited the Na+-independent movement of Cl- and reduced the transfer of Cl- linked with Na+.

Interrelationships between dietary concentrations of sodium, potassium and chloride in laying hens.

Twelve diets, representing the factorial combination of two concentrations of Cl- (0.8 and 1.4 g/kg), three concentrations of Na+ (0.

Changes in hydromineral metabolism in diarrhoeic rabbits. 2. Study of the modifications of electrolyte metabolism.

The study of the equilibrium of the main electrolytes (Na+, K+, Cl-), in plasma and intestinal content and the evolution of the partial plasma (Na+, K+, Cl-) in the young rabbit suffering from diarrhoea revealed disturbances of the mineral metabolism. Mineral losses were lower in sick animals than in controls. When the reduction of ingested matter was taken into account, the ion balance showed a deficit.

Studies on the avian shell gland during egg formation: mucosal intracellular pH.

1. The intracellular pH and the extracellular fluid volume of the shell gland mucosa were determined. 2.

[Water and electrolyte movements across the duodenal mucosa in laying hens during in vivo perfusion].

The net water movements through the duodenum in laying hens are directly dependent on the applied osmotic gradient. The passive water permeability (Lp) of the mucosa is 6 times higher during absorption (mucosa to serosa: 70 microliter/h/mOsm) than in the opposite direction (secretion: 11.5 microliter/h/mOsm) and its semi permeability is 0.

The effect of induced metabolic acidosis on vitamin D3 metabolism in rachitic chicks.

The metabolism of vitamin D3 was studied in 3-week-old, vitamin D deficient chicks, fed since hatching with a diet containing 3% ammonium chloride, 1% calcium, and 0.7% phosphorus. When kidney homogenates were incubated in vitro with [3H]25-(OH)D3, the production of 1,25-(OH)2D3 was reduced by 40% in acidotic birds.

Studies on the avian shell gland during egg formation: aqueous and electrolytic composition of the mucosa.

The intracellular composition of the avian shell gland mucosa was studied at six stages of egg formation. 2. Total water content of the mucosa before shell calcification was 4-8 kg/kg dry weight (dw) and rose to 6-6 kg/kg dw during shell formation; 60% of the increase was intracellular and 40% extracellular.

Composition of crop and gizzard contents in the laying hen.

Crop and gizzard contents were analysed at six stages of egg formation. 2. The crop was empty during the day and full during the night while the gizzard contained a constant amount of dry matter.

Ionic constituents and osmolality of the small intestinal fluids of the laying hen.

1. The osmotic pressure of the liquid phase of the contents of the small intestine is always hypertonic to plasma and not affected by egg formation. 2.

A comparison of the osmotic pressures along the digestive tract of the domestic fowl and the rabbit.

1. The osmotic pressures of the contents of the alimentary tract from the adult hen and cockerel and rabbit were measured. 2.