Liver histology and histomorphometry in hybrid sorubim (Pseudoplatystoma reticulatum × Pseudoplatystoma corruscans) reared on intensive fish farming

This study aimed to characterize the liver histology and histomorphometry in sorubim hybrid of different categories (nursery, growth and grow‐out) reared on fish farming. The categories were defined considering body weight (BW): nursery category (n = 5): BW = 37.06 ± 6.00 g (31.6–45.3 g); growth category (n = 5): BW = 310.40 ± 53.80 g (242.1–376.4 g) and grow‐out category (n = 5): BW = 874.28 ± 27.59 g (846.2–913.1 g). Liver fragments were processed to paraffin inclusion, and sections were stained by haematoxylin and eosin (H&E), PAS (Periodic Acid Schiff) and Perl's staining to histology, histomorphometry and density volumetric of liver structures; glycogen analysis and to detect ferric irons (Fe³⁺) respectively. The hepatosomatic index decreased between the categories (P < 0.01). The percentage of PAS‐positive hepatocytes in the nursery category was higher (P < 0.05) in relation to the growth and grow‐out categories. The hepatocytes from all fish were positive to Perl's staining. The density volumetric of liver structures did not differ among categories except to blood vessels were higher (P < 0.01) in the nursery and growth. The area (μm²) and perimeter (μm) of hepatocytes, and the area (μm²), perimeter (μm) and volume (μm³) of the nuclei from grow‐out fish were lower (P < 0.01) than those from the nursery and growth categories. Changes in morphometric characteristics of hepatocytes may result from metabolic changes associated with body growth surubins; therefore, these morphometric characteristics of liver tissue can be used as functional biomarkers for the assessment of fish health and nutrition status.     

Haematologic and immunologic parameters of bullfrogs,Lithobates catesbeianus,fed probiotics

The effects of two probiotics (P₁–Lactobacillus acidophilus, Bifidobacterium bifidum and Enterococcus faecium and P₂–Bacillus subtilis) supplemented to commercial feed (40% crude protein) on the haematological and immunological parameters of the bullfrog Lithobates catesbeianus were studied. Two doses of each probiotic (5 and 10 g kg^?1 of food) were added to the diets and fed to frogs, totalling five treatments over 112 days. Haematological analyses consisted of total and differential leucocyte counts, erythrocyte and thrombocyte counts, haematocrit, haemoglobin levels and RBC indices (mean corpuscular volume, mean corpuscular haemoglobin – and mean corpuscular haemoglobin concentration) and the immunological parameters included phagocytic capacity and phagocytic index of peritoneal phagocytes. The results showed that the probiotics did not significantly influence any of the haematological parameters measured. However, immunological assays showed that the probiotics had an immunostimulating effect. The greatest effects were seen with probiotic P₁ fed at a dose of 10 g kg^?1 of diet and probiotic P₂ fed at 5 g kg^?1 of diet.     

NITROGEN USE EFFICIENCY IN UPLAND RICE GENOTYPES

Nitrogen (N) deficiency is one of the most yield-limiting nutrients in upland rice growing regions word wide. A greenhouse experiment was conducted with the objective to evaluate nineteen upland rice (Oryza sativa. L.) genotypes for N use efficiency. The soil used in the experiment was an Oxisol and two N levels used were without N application (low level) and an application of 400 mg N kg^?1 of soil (high level). Grain yield and yield components and N uptake parameters were significantly affected by N and genotype treatments. Regression analysis showed that plant height, shoot dry weight, number of panicles per pot, number of grains per panicle, grain harvest index, N uptake in shoot and grain were having significant positive relation with grain yield. Nitrogen concentration of 6.4 g kg^?1 in the shoot is established as deficient level and 9.5 g kg^?1 as sufficient level at harvest. Agronomic efficiency of N (grain yield/unit of N applied) and N utilization efficiency (physiological efficiency X apparent recovery efficiency) were significantly different among genotypes. These two N use efficiencies were having significant quadratic relationship with grain yield. Soil pH, exchangeable soil Ca and base saturation were having significantly positive association with grain yield. However, soil extractable phosphorus (P), potassium (K), hydrogen (H⁺), aluminum (Al) and cation exchange capacity were having significantly negative association with grain yield.     

Delinted cottonseed in diets for finishing sheep

Tropical Animal Health and Production - The use of agricultural by-products might provide an important alternative to improve animal agriculture and to reduce feeding costs. The effects of...     

Montenegro's skin reactions and antibodies against different Leishmania species in dogs from a visceral leishmaniosis endemic area

In this study, humoral (circulating anti-Leishmania antibodies) and cellular (Montenegro's skin test) immune responses of dogs from an endemic area of visceral leishmaniosis were tested using Leishmania chagasi, Leishmania amazonensis and Leishmania braziliensis antigens. The antibody response was tested in three animal groups, selected according to their anti-L. chagasi antibody activity, as measured by ELISA in the serum: 19 negative (O.D. below 0.30), seven with undefined (O.D. between 0.40 and 0.70) and 12 positive (O.D. above 1.0) ELISA result. In the group of animals with positive ELISA, the antibody activity against L. chagasi antigens (mean O.D.=1.31) was significantly higher (ANOVA, P<0.01) than against L. amazonensis (mean O.D.=0.88) or L. braziliensis (mean O.D.=0.87) antigens. The Montenegro's skin test results obtained with L. chagasi and L. braziliensis antigens showed a fair agreement (kappa=0.309). The same was observed when antigens from L. braziliensis and L. amazonensis were compared (kappa=0.374), whereas a moderate agreement between the results from tests performed with L. chagasi and L. amazonensis antigens was observed (kappa=0.530). The induration areas obtained with L. braziliensis antigen were smaller than those obtained with the other antigens. The data presented herein indicate that the use of antigens from different Leishmania species may interfere with the results of the immunological tests performed in dogs in an endemic area of visceral leishmaniosis.     

Association of macrophage and lymphocyte infiltration with outcome in canine osteosarcoma

Immunotherapeutic strategies have shown promise for the treatment of canine osteosarcoma (cOSA). Very little is known about the immune microenvironment within cOSA, however, limiting our ability to identify potential immune targets and biomarkers of therapeutic response. We therefore prospectively assessed the disease‐free interval (DFI) and overall survival time (ST) of 30 dogs with cOSA treated with amputation and six doses of adjuvant carboplatin. We then quantified lymphocytic (CD3+, FOXP3+) and macrophage (CD204+) infiltrates within the primary tumours of this cohort using immunohistochemistry, and evaluated their association with outcome. Overall, the median DFI and ST were 392 and 455 days, respectively. The median number of CD3+ and FOXP3+ infiltrates were 45.8 cells/mm² (4.6‐607.6 cells/mm²) and 8.5 mm² (0‐163.1 cells/mm²), respectively. The median area of CD204+ macrophages was 4.7% (1.3%‐23.3%), and dogs with tumours containing greater than 4.7% CD204+ macrophages experienced a significantly longer DFI (P = 0.016). Interestingly, a significantly lower percentage of CD204+ macrophages was detected in cOSA arising from the proximal humerus compared to other appendicular bone locations (P = 0.016). Lymphocytic infiltrates did not appear to correlate with outcome in cOSA. Overall, our findings suggest that macrophages may play a role in inhibiting cOSA progression, as has been suggested in human osteosarcoma.     

In silico and gene expression analysis of the acute inflammatory response of gilthead seabream (Sparus aurata) after subcutaneous administration of carrageenin

Fish Physiology and Biochemistry - Inflammation is one of the main causes of loss of homeostasis at both the systemic and molecular levels. The aim of this study was to investigate in silico the...     

High immune diversity in farmed Atlantic salmon (<Emphasis Type="Italic">Salmo salar</Emphasis> L.)

As with any other intensively farmed animal species, the Atlantic salmon has been selectively bred and cross-bred to maximize desirable traits. Selection tends to diminish genetic diversity in target populations, which among other negative effects is hypothesized to decrease their capacity to confront a broad variety of pathogens. We have analyzed mitochondrial (mtDNA) as well as major histocompatibility complex (MHC) DNA sequences from individuals collected from a single aquaculture cage in southern Chile. Interestingly, only two mtDNA haplotypes were obtained; however, several different MH alleles were detected, with divergence values that were compared with those of natural populations of salmonids. Thus, it seems evolutionary processes responsible of keeping MH diversity in the wild managed to retain MH variability in farmed Atlantic salmon, maintaining high immune diversity despite the generally lower levels of observed neutral genetic diversity.     

Effect of a size-based selection program on blood metabolites and immune response of Litopenaeus vannamei juveniles fed different dietary carbohydrate levels

Blood metabolites in wild and seventh-generation cultivated shrimp were measured to determine how size-based selection could alter the nutritional and immunological conditions of Litopenaeus vannamei. Wild L. vannamei juveniles and a sample of seventh-generation cultured shrimp were acclimated under identical conditions. During 55 days, shrimp were fed a high (HCHO: 44%) or a low (LCHO: 3%) carbohydrate diet for 55 days. Wild shrimp showed a direct relation between dietary CHO and lactate, protein and hemocyte levels indicating that dietary CHO was used for protein synthesis via transamination pathways. In seventh-generation cultured shrimp these parameters were inversely proportional to dietary CHO level, indicating the capacity to synthesize protein from dietary CHO was repressed in cultured shrimp. Farmed shrimp showed a limited capacity to respond to LCHO diets demonstrating high protein dependence in their metabolism and immune response. These results demonstrate that during size-based breeding programs other metabolic process than CHO catabolism can be selected. The incapacity of shrimp to use dietary CHO could limit protein reduction of diets and limit the efforts of the shrimp industry to be ecologically and environmentally profitable.     

On the independence between clupeid stocks and their recruitment

The statistical independence between the reproductive stock and its corresponding recruitment to a fishery was tested for 43 stocks of clupeids in the Ransom Myers database by using the chi-squared test of a contingency table. The method was validated by simulating stock and recruitment (SR) contingency tables for data close to hypothetical SR curves that represent several known phenomena. The clupeid SR data were grouped by the criteria of percentile points to build the contingency tables. The independence test of the clupeid stocks was rejected in only 15 cases, thus the independence hypothesis was sustained in the remaining 28 cases. This demonstrates that fitting an SR model in these clupeid stocks is not justified because their abundance could be affected by several causes other than reproductive stock fluctuations.