Estimation of genetic parameters for body areas in Nile tilapia measured by digital image analysis.

Digital image analysis is a practical, non-invasive, and relatively low-cost tool that may assist in the evaluation of body traits in Nile tilapia, being particularly useful for assessing difficult-to-measure variables, such as body areas. In this study, we aimed to estimate variance components and genetic parameters for body areas of Nile tilapia obtained by digital images. The data set comprised body weight (BW) records of 1,917 pond-reared fish at 366 days of age. Of this total, 656 animals were photographed and subjected to image analysis of trunk area (TA), head area (HA), caudal fin area (CFA) and fillet area (FA). Heritabilities and genetic correlations were estimated through multiple-trait models based on Bayesian inference. Heritability estimates for BW, TA, HA, CFA and FA were 0.25, 0.23, 0.26, 0.21 and 0.25, respectively. Genetic correlations between the traits were high and positive, ranging from 0.70 to 0.98. We highlight the genetic correlation between BW and TA (rG  = 0.98) and FA (rG  = 0.97). In view of the observed results, it can be concluded that trunk and fillet areas obtained by digital image analysis can lead to indirect genetic gains in weight and other body areas. In addition, the areas studied have potential as a selection criterion and may assist in studies on changes in the body shape in Nile tilapia.

Effects of combined use of keratinolytic enzymes and sugarcane fibre on the hairball excretion in cats.

Grooming is a natural hygienic behaviour of cats that favours the formation of hairballs. Increased fibre concentration in the diets is a strategy to minimize hairball formation, but it is not fully effective. Because cat hair is formed mostly by keratin, the addition of keratinases in the diets might be an alternative for hairball control. Thus, the objective was to evaluate the effect of the combined use of sugarcane fibre and a protease complex to reduce the hairball excretion in cats. Twenty-four adult cats were divided into four treatment groups (n = 6 per treatment) in a 2 × 2 factorial arrangement. Treatments were as follows: control diet (Control; containing low concentration of insoluble fibre, 5.34% of total dietary fibre), control diet plus enzyme (Co-e), high-fibre diet (HF; containing high amounts of insoluble fibre, 17.8% of total dietary fibre), and HF diet plus enzyme (HF-e). Proteases from Bacillus licheniformis PWD-1 were administered orally (5 mg/day) as gastro-resistant capsules. Total collection of faeces was carried out to determine the number of excreted hairballs and the coefficient of total tract apparent digestibilities (CTTAD) of the diets. Separate addition of insoluble fibre (HF; p = .5947) or enzyme complex (Co-e; p = .3633) had no effect on the hairballs excreted in the faeces. However, the combined use of insoluble fibre and enzymes (HF-e) reduced (p = .0344) the total number of hairballs excreted. The size distribution of hairballs (small, medium, or large) was not affected by treatments (p = .3763). The CTTAD of crude protein was not affected by protease addition (p = .781) but was reduced by HF and HF-e treatments. Sugarcane fibre associated to keratinolytic enzymes reduces the hairball excretion in cats. This strategy can be adopted for this purpose; however, methods for faecal hairball quantification must be improved. If you have not already completed a Copyright Transfer Agreement, please log on to Wiley Author Serivices, https://authorservices.wiley.com/bauthor/, sign-in and complete the License Agreement form".

Effects of dietary supplementation with a microalga (Schizochytrium sp.) on the hemato-immunological, and intestinal histological parameters and gut microbiota of Nile tilapia in net cages.

Nutritional improvements in intensive aquaculture production systems is necessary for the reduction of stress, maximum utilization of nutritional components, and expression of the genetic potential of fish. The objective of this study was to evaluate the hemato-immunological, and histological parameters and gut microbiota of Nile tilapia fed with the microalga Schizochytrium sp. Males of Nile tilapia were distributed among eight net cages (6 m3), and fed for 105 days with two diets: control (CON), without Schizochytrium sp., and supplemented (SUP), with 1.2% Schizochytrium sp. in the diet. The final weight, mortality, hematocrit, total erythrocyte count (RBC), hemoglobin, hematimetric indices, white blood cell count (WBC), total protein, and serum lysozyme were measured. Alterations in intestinal morphology were evaluated. The gut microbiota was evaluated with next-generation sequencing. No significant differences (p>0.05) were found in the final weight and mortality between diets. Regarding the hematological parameters, a difference (p<0.05) was detected only in RBC, with there being lower values in the SUP, although this group also showed a tendency toward having an increased mean corpuscular hemoglobin level. There were no differences (p>0.05) in total protein and serum lysozyme concentrations or in WBCs between diets, except for lymphocytes, which presented lower values (p<0.05) in the SUP, suggesting immunomodulation by the polyunsaturated fatty acids present in the microalga. There was no difference (p>0.05) in the intestinal morphology between diets. Metagenomic data indicated greater richness (represented by the Chao index) and a higher abundance of the bacterial phylum Firmicutes in the gut microbiota of the tilapia fed with the SUP diet, demonstrating that the digestion and use of the components of the microalga could influence the microbial community. The results indicated that the microalga had modulatory effects on blood cells and the intestinal microbiota, without affecting the structure and integrity of the intestinal villi.

Ovopel and carp pituitary extract for the reproductive induction of Colossoma macropomum males.

The objective of this study was to evaluate Ovopel and carp pituitary extract (CPE) in the reproductive induction of Colossoma macropomum males. Nine treatments were tested in triplicate, totaling 27 experimental units. C. macropomum breeders were subjected to the following treatments: 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 Ovopel pellet/kg; 2.5 mg CPE/kg (traditional protocol); and a control treatment (no hormone). Breeders under hormone treatment produced a larger (P < 0.05) semen volume (2.4 ± 0.7 to 4.2 ± 0.3 mL) compared with the control (0.9 ± 0.4 mL). Sperm concentration did not differ significantly among treatments (7.2 × 109 ± 1.7 to 10.8 × 109 ± 2.6 spermatozoa/mL). Total sperm count was higher (P < 0.05) after treatment with 0.3, 0.4, and 0.6 Ovopel pellet/kg (41.6 ± 9.3 to 42.3 ± 10.5 × 109 spermatozoa) than the other Ovopel treatments (20.0 ± 2.4 to 26.9 ± 8.2 × 109 spermatozoa) and control (6.6 ± 1.1 × 109 spermatozoa), but did not differ significantly from CPE (33.7 ± 3.2 × 109 spermatozoa). Sperm motility was higher (P < 0.05) in the CPE treated, and 0.2, 0.3, and 0.7 Ovopel pellet/kg (88.3 ± 2.9 to 90.0 ± 5.0) breeders when compared with the other treatments (70.0 ± 10.0 to 78.3 ± 5.8), except for the 0.4 pellet/kg (81.7 ± 2.9) treatment, which did not differ significantly from any of the treatments. The motility period of the spermatozoa did not differ significantly among treatments (93.5 ± 15.7 to 120.0 ± 7.6 s). For the sperm morphological analysis, occurrence of normal spermatozoa was similar across the treatments, with three sperm abnormalities (short tail, bent tail, and detached head) differing (P < 0.05) among the treatments. Ovopel efficiently induced reproduction of C. macropomum breeders, with treatment using 0.3 and 0.4 Ovopel pellet/kg and CPE providing the best semen characteristics.

Ovopel and Carp Pituitary Extract as Spawning Inducers in Males of the Amazon Catfish Leiarius marmoratus (Gill, 1970)

The objective of this study was to evaluate Ovopel and carp pituitary extract as spawning inducers in the males of the Amazon catfish L. marmoratus. The following treatments, applied in a single dose, were studied: 0.2, 0.4 and 0.6 Ovopel pellet/kg live weight, and 2.5 mg carp pituitary extract/kg live weight. Each treatment was repeated four times. No significant difference in sperm volume, motility and vigor, time of motility, sperm count, or percentage of normal and abnormal spermatozoa was observed between the treatments. There was also no significant difference in terms of primary or secondary sperm defects, except for the secondary defect of loose heads, which was less frequent in the treatments using 0.4 and 0.6 Ovopel pellet/kg live weight. It was concluded that Ovopel could replace carp pituitary extract for induction spawning in the males of the Amazon catfish L. marmoratus.

Resposta imune-humoral e celular em bovinos da raça Nelore imunizados com extrato de larvas (L2 e L3) de Dermatobia hominis (Linnaeus Jr., 1781) / Immune humoral and cellular response of nelore bovines immunized with larvae extract (L2 and L3) of Dermatobia hominis (Linnaeus Jr., 1781)

As larvas da Dermatobia hominis provocam lesões ulcerativas, danificando o tecido subcutâneo e conseqüentemente a pele do hospedeiro. O couro é o subproduto que sofre maior depreciação, o que, muitas vezes, impossibilita seu aproveitamento na industrialização. Atualmente o controle químico é utilizado como forma de combate à dermatobiose, entretanto, leva ao acúmulo de substâncias tóxicas nos animais e no ambiente. No presente trabalho, foram avaliadas as respostas imune-humoral e celular de bovinos imunizados com extrato antigênico preparado com larvas de D. hominis. Três grupos de oito bezerras da raça Nelore com 10 meses de idade foram usados, tendo o primeiro grupo (A) recebido aplicação de extrato imunogênico de larvas de D. hominis, com intervalos de quinze dias; o grupo (B), utilizado como controle, não recebendo nenhum tipo de tratamento; e o grupo (C) recebendo o tratamento ectoparasiticida à base de Dichlorvos associado a Cypermetrina. Neste mesmo período, foram avaliados o leucograma e os níveis de IgG contra D. hominis pela técnica de enzimoimunoensaio-ELISA. Quanto à avaliação da imunidade humoral, verificou-se que os animais do grupo A apresentaram maior produção de IgG contra D. hominis, com níveis máximos de anticorpos circulantes aos 45 dias após a primeira imunização. Estes animais também apresentaram maior produção de neutrófilos, eosinófilos e monócitos que os dos grupos B e C. O número de nódulos de larvas encontrado nos animais do grupo C foi 148,3 por cento maior que nos animais dos grupos A e B. A comprovação da resposta imune celular e humoral, parcialmente caracterizadas, bem como a redução do número de nódulos, são indicadores que a imunização contra D. hominis foi parcialmente protetora para os bovinos imunizados.

Dermatobia hominis larvae cause ulcerative lesions and damage to subcutaneous tissue and skin of the host. Leather is the subproduct which undergoes major depreciation, making it difficult to industrial use. Nowadays, the chemical control is utilized against dermatobiosis, therefore it leads to rising toxic chemicals in the animals and environment. The immunological challenge with D. hominis larval extract may represent an important altervative for this parasitosis control. Humoral and cellular immune responses were tested in bovine using an antigenic extract prepared with D. hominis larvae. Three groups of 10 months old Nelore females were used. The first group (A) received immunogenic larval extract of D. hominis with fifteen-days interval between injections; the group (B) was the control and has not received any sort of treatment; and the group (C) received an ectoparasitecide treatment based on Dichlorvos associated to Cypermetrina. Aditionally, leucogram and levels of IgG against D. hominis by immunoassay technique were evaluated. As for the humoral immunity, animals from group A presented higher IgG production against D. hominis with maximum levels of circulating antibodies at the 45th day after the first injection. These animals also showed higher production of neutrophils, eosinophils and monocytes than those from groups B and C. The number of D. hominis larvae nodules observed in animals from the group C was 148.3 percent larger than those from group A and B. The evidence concerning both cellular and humoral immune responses as well as the reduction on nodules number are an indication that the immunization against D. hominis was partially protective for the immunized bovines.