The changes in ocean chemistry stemming from anthropogenic CO2 release--termed ocean acidification (OA)--are predicted to have wide-ranging effects on fish and ultimately threaten global populations. The ability of fish to adapt to environmental change is currently unknown, but phenotypic plasticity has been highlighted as a crucial factor in determining species resilience. Here we show that red drum, a long-lived estuarine-dependent fish species native to the Gulf of Mexico, exhibit respiratory plasticity that increases CO2 excretion capacity when acclimated to OA conditions. Specifically, fish exposed to 14 days of 1000 µatm CO2 had a 32% reduction in branchial diffusion distance and increased expression of two putative CO2 channel proteins--rhag and rhcg1. No changes were observed in the erythrocyte CO2 transport pathways. Surprisingly, no significant changes in blood chemistry were observed between acclimated and acutely challenged animals; however, a non-significant 30 % drop in the magnitude of plasma C(CO2) elevation was observed. Reduced diffusion distance also comes with the cost of increased diffusive water loss, which would require greater osmoregulatory investment by the animal. OA exposure induced increased gill Na(+), K(+) ATPase activity and intestinal nkcc2 expression, supporting both the presumed osmotic stress and increased osmoregulatory investment. However, no differences in standard metabolic rate, maximum metabolic rate or aerobic scope were detected between control and OA acclimated individuals. Similarly, no differences in critical swim speed were detected between groups, suggesting the energetic cost related to respiratory plasticity is negligible against background metabolism. The current study demonstrated that red drum exhibit respiratory plasticity with only mild physiological trade-offs; however, this plasticity is insufficient to fully offset the OA-induced acid-base disturbance and as such is unlikely to impact species resilience.
The intensification of animal production systems presents a potential impact on the welfare of animals. The objective of this work was to assess the welfare of quail Coturnixcoturnix japonicain two maintenance systems: battery cages (BC),and enriched aviary (EA),with saw-dust bedding, sand-bathing area and nests. The experiment procedure involved eight animals per holding area and four repetitions per treatment, an overall of 64 quails. Welfare was assessed through behavioral freedom, sanitary freedom (feather condition and injuries), blood analyses and glicocorticoid metabolites measurement in droppings. Results are presented in the BC order, followed by EA. Water drinking behavior and agonistic behavior were different between treatments (P<0.05). Feather condition was adequate in both treatments, except for the head in BC quails. Blood data were statistically different forred blood cells, hematocrit, hemoglobin, blood proteins, eosinophils, heterophils, lymphocytes and heterophil: lymphocyte ratio. Glicocorticoid metabolites levels were significantly different between maintenance systems. The behavioral and physiological welfare indicators showed higher welfare degree for quails in enriched aviary as compared to battery cages system.
Enzyme activity was evaluated in the intestine of juvenile pacu, Piaractus mesopotamicus, fed diets containing 0, 10 or 20 % of lyophilized bovine colostrum (LBC) inclusion for either 30 or 60 days. The enzymes intestinal acid and alkaline phosphatase (ACP and ALP, respectively), nonspecific esterase (NSE), lipase (LIP), dipeptidyl aminopeptidase IV (DAP IV) and leucine aminopeptidase (LAP) were studied using histochemistry in four intestinal segments (S1, S2, S3 and rectum). Moderate activity of the DAP IV was detected in the three last intestinal segments, but no differences among the treatments were detected. Enzymes LAP, NSE and LIP were weakly stained in all intestinal segments and the inclusion of 10 or 20 % of LBC in the diet commanded a moderate reaction to NSE in the S3 segment at day 60. ACP activity was detected only in the brush border of the S1 segment of fish fed 0 % LBC for either 30 or 60 days. The activity of ALP was very strong in the first intestinal segment, but a weak reaction was seen in the last segments. The inclusion of 20 % of LBC changed the pattern of staining to the ALP, eliciting moderate staining in S2 at day 30 and S1 at day 60. The consumption of diets containing LBC by juvenile pacu did not have significant implications in intestinal enzymatic activity, which still was not fully stimulated.
Enteric histology of newborn goat kids fed lyophilized bovine colostrum (LBC) was studied. At 0, 7, and 14 h of life 15 male newborns received 5% of body weight of lyophilized bovine colostrum and 14 male newborns goat colostrum (GC), both with 55 mg/ml of IgG. Samples of duodenum, jejunum, and ileum were collected at 18, 36, and 96 h of life for analyses of villus height, crypt depth, muscle layer thickness, partial volume of the absorptive mucosa (Vv), density of the absorptive mucosa (Sv), and quantification of goblet cells. Three animals were sampled without colostrum intake (0 h). The histomorphometry was not different between GC and LBC in all segments. In the jejunum, the villus height differed in sampling times (36 h > 0 h and 18 h). The maximum villus height was observed in the jejunum. In the jejunum, crypt depth differed in the sampling times (96 h > 0 and 18 h). Interaction between intestinal segment and sampling times was observed to crypt depth (duodenum 18 h > jejunum 18 h and duodenum 96 h > ileum 96 h). In the ileum, the muscle layer thickness differed in the sampling times (36 h > 0 and 18 h and 96 h > 0 h). The greatest thickness of muscle layer was observed in the duodenum and at 96 h the muscle layer was thicker than at 18 h. The ileum showed the highest Vv at 36 h. The Vv was the highest in the jejunum and higher at 36 h than at 96 h. In the jejunum, an interaction between the treatment and sampling times to goblet cells number (LBC 18 h < GC 18 h and GC 96 h > LBC 96 h) was observed. The ileum showed the greatest number of goblet cells. The ingestion of lyophilized bovine colostrum did not determine any consequences for enteric histology in the first 4 days of goat kids' life.
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