Sérgio do Nascimento Kronka

Fauna parasitária de peixes oriundos de "pesque-pagues" do município de Franca, São Paulo, Brasil. II. Metazoários

Metazoan fauna from cultivated fishes (N = 433) in two feefishing farm of Franca, State of Sao Paulo, Brazil, was studied during a period of April 1997 through March 1999. Specimens of piaucu Leporinus macrocephalus Garavello & Britski, 1988 (Anostomidae), pacu Piaractus mesopotamicus Holmberg, 1887 (Characidae), carp Cyprinus carpio Linnaeus, 1758 (Cyprinidae), Tillapia rendalli Boulenger, 1896 (Cichlidae), nile-tilapia Oreochromis niloticus Linnaeus, 1758 (Cichlidae), matrinxa Brycon cephalus Gunther, 1869 (Characidae) and tambacu hybrid (male of P. mesopotamicus x female of Colossoma macropomum Cuvier, 1818) were collected. A total of 29.3% was parasitized by monogenean, 9.7% with crustacean (copepodits and adults of Lernaea cyprinacea Linnaeus, 1758 and Argulus sp.) and 1.6% with myxosporean (Henneguya piaractus Martins & Souza, 1997 and Myxobolus colossomatis Moinar & Bekesi, 1993).The most susceptible species to myxosporean infestation was P. mesopotamicus. L. macrocephalus and P. mesopotamicus that showed a higher susceptibility to Argulus sp infestation. It was not observed significant difference (P > 0.05) in the seasonal variation of L. cyprinacea infection of all species. L. macrocephalus, P. mesopotamicus and tambacu showed a great number of P. pillulare with no significant difference (P > 0.05) between them. Monogenean infections were observed in all examined species, without significant difference (P > 0.05) in the seasonal variation. Nevertheless, occurrence of monogenean was higher in P. mesopotamicus and lower in Nile-tilapia. By the other hand, parasites number collected from P. mesopotamicus was lower in the winter. Copepodits of L. cyprinacea were found in the gills of P. mesopotamicus, tambacu and L. macrocephalus. However, adults of L. cyprinacea were observed only in the P. mesopotamicus and tambacu.

Evaluation of the haematological parameters in Piaractus mesopotamicus Holmberg (Osteichthyes, Characidae) with Argulus sp. (Crustacea, Branchiura) infestation and treatment with organophosphate

Haematological parameters as erythrocytes, leukocytes and plasma glucose in Piaractus mesopotamicus Holmberg, 1887 were analyzed. Fish were parasitized with Argulus sp. (Crustacea, Branchiura) and treated with 0.4 mg of thriclorphon 500/L water. The effects of parasitism and the action of the treatment were evaluated. Parasitized fish showed greater number of monocytes (P>0.05) and special granulocitic cells (P 0.05). Organophosphate treatment presented significantly reduction (P>0.05) in red blood cells (RBC) and hemoglobin.

Susceptibility of the cattle tick Boophilus microplus (Acari: Ixodidae) to isolates of the fungus Beauveria bassiana

The susceptibility of the tick Boophilus microplus to Beauveria bassiana was evaluated by inoculating eggs, larvae and engorged females of the tick with five fungal isolates at concentrations of 106, 107 and 108 conidia/ml. Tick eggs (0.25 g) were immersed in 1 ml of a suspension of the different conidial concentrations for 1 min. Similar exposure was performed by immersion of 2000 larvae and homogeneous groups of nine engorged females in 2 and 20 ml of conidial suspension, respectively. Treated eggs, larvae and adults were placed in an incubator at 27 ± 1 °C and relative humidity above 80% for evaluation of the fungal action. All fungal isolates applied at all conidial concentrations reduced the hatching rate of larvae from treated eggs by 1.36–65.58% and increased the mortality rate of inoculated larvae by 0.8–70.49%. In the bioassay with engorged females, oviposition period was reduced by 9.69–47.80%, egg mass weight by 4.71–53.87%, estimated reproduction by 8.3–60.62%, egg production index by 5.03–54.20%, percent larval hatching by 0.27–13.96%, and the mortality rate of treated females was increased by 96.60–100%. The reduction of the estimated reproduction obtained for the treated groups ranged from 8.37 to 64.52%. The sporulation of the pathogen on dead females ranged from 3.70 to 88.88% depending on the isolate and concentration used. Isolates AM 09, CB 7 and JAB 07 were the most effective and effectiveness increased with increasing concentrations of conidia in the suspensions.

Hepatic concentration of heat shock protein 70 kD (Hsp70) in broilers subjected to different thermal treatments

1. The relationship between repeated thermal treatments and hepatic synthesis of Hsp 70 was studied in broiler chickens. 2. Sixty broilers were submitted to 5 different treatments (12 birds each) from day 1 to day 42. Four groups were kept in a thermoneutral environment and subjected to 0, 1, 2 and 3 heat stress episodes at 35 degrees C for 4 h per week (TN-0, TN-1, TN-2 and TN-3, respectively). The last group (HT-35) was reared at a room temperature of 35 degrees C. 3. From 39 to 42 old, the birds experienced acute heat stress at 41 degrees C. Resistance to heat stress was evaluated by the time taken for rectal temperature to increase by 3 degrees C above the pre-treatment value. Livers were collected (before and after heat stress) and Hsp70 was determined using Western Blot analysis with monoclonal anti-Hsp70 antibody. 4. Resistance to heat stress and concentration of Hsp70 were higher in those birds subjected to more heat stress episodes during the experimental period (TN-3) and HT-35. A positive correlation was observed between Hsp70 concentration and the time taken for a 3 degrees C increase in rectal temperature (r = 0.42; P<0.01). 5. Exposing birds to episodes of heat stress (35 degrees C) during rearing may improve their resistance to acute heat stress, but the previous thermal history did not seem to influence the hepatocyte Hsp70 content after exposure to more severe heat stress (41 degrees C).

Desempenho de bovinos confinados alimentados com dietas à base de farelo de algodão, uréia ou amiréia

The objective of this experiment was to evaluate the performance of feedlot beef cattle fed diets supplemented with protein concentrate based on cottonseed meal (CSM) urea (UR) or starea (ST), using corn silage as forage. The feedlot period was 80 days. The diets were constituted maintaining the forage:concentrate proportion in the 63:37 level, with nearly 13% CP. No difference was observed in daily weight gain during the experimental period among the CSM, UR or ST treatments (1.14, 1.17, and 1.23 Kg/animday) or in the dry matter intakes in % LW (2.63, 2.60, and 2.60), g/kg 0.75 •day (136.19, 134.74, and 134.81) or kg/anim.•day (9.42, 9.35, and 9.40), respectively. The CP intakes values were 1.28, 1.24, and 1.34 kg of CP/anim.•day and 18.54, 17.86, and 19.24 g/kg .75 •day for the CMS, UR or ST treatments and they did not differ among each other. Values of feed:gain ratios obtained for dry matter were 8.41, 8.01, and 7.67 kg DMI/kg DWG and for the protein:gain ratios, 1.15, 1.06, and 1.09 kg CPI / Kg DWG, respectively, for the CPM, UR and ST treatments, that were similar.

Effects of turmeric and its active principle, curcumin, on bleomycin-induced chromosome aberrations in Chinese hamster ovary cells

Antioxidantes de ocorrencia natural tem sido exaustivamente estudados quanto a sua capacidade de proteger organimos e celulas contra danos oxidativos. Muitos constituintes das plantas, incluindo curcuma e curcumina, parecem ser potentes antimutagenos e antioxidantes. Os efeitos de curcuma e curcumina na frequencia de aberracoes cromossomicas induzidas pelo agente radiomimetico bleomicina (BLM) foram investigados em celulas do ovario de hamster chines (CHO). Tres concentracoes de cada droga, curcuma (100, 250 e 500 mg/ml) e curcumina (2,5, 5,0 e 10 mg/ml), foram combinadas com BLM (10 mg/ml) em celulas CHO tratadas durante as fases G1/S, S ou G2/S do ciclo celular. Nem curcuma nem curcumina evitaram o dano cromossomico induzido pela BLM em fase alguma do ciclo celular. Ao contrario, a potenciacao da clastogenicidade da BLM pelo curcumina foi nitidamente observada em celulas tratadas durante as fases S e G2/S. A curcumina tambem se mostrou clastogenica na dose de 10 mg/ml nos protocolos de tratamento de 9 e 13 h. Contudo, o mecanismo exato pelo qual a curcumina produziu efeitos potenciadores e clastogenicos permanece desconhecido.

Efeito do peso de tilápia no nilo (Oreochromis niloticus) sobre e rendimento e a qualidade de seus filés defumados com e sem pele

The objective of this study was to evaluate the effect of different weights of Nile tilapia (Oreochromis niloticus) on yield and quality of smoked and in natura fillets, with and without skin. One hundred tilapias, divided into three weight classes (C1=500-600g; C2=601-700g; C3=701-800g) were used. Two fillet types, with skin and without skin were removed from each sample, salted and hot smoked. Weight affected yield of in natura (C1 = 38.54; C2 = 40.23 e C3 = 40.47%) and smoked fillets (C1 = 22.97; C2 = 24.51 e C3 = 24.68%), and in natura fillet mass index (C1 = 36.69; C2 = 39.45 e C3 = 41.18 g.cm-2). The latter was higher in classes C2 and C3. Fillet with skin had a higher (p<0.05) water activity (0.99) rate than that of fillet without skin (0.98). Salt rate was higher (p<0.01) in smoked fillets than in natura ones. It was observed higher salt levels in the C1 skinless class. With the exception of a* and b* in natura fillet, no difference was reported in color. Smoked fillets from C3 class fish were more acceptable by judges. In larger fish the equation Y= -21.52 + 0.16034X (r=0.80), where X is the weight of fish, may be employed to calculate smoked fillets size, while Y= -17.74 + 0.14198X (r=0.81) for smoked skin-less fillets. Regardless of skin presence, the smoked fillets from largest fishes (C2 and C3 classes) yielded better results (approximately 24%), as well as in the sensorial analysis, related to salt ratio and general acceptance. Fillets in natura showed low values to a* and b*. Weight classes and skin presence in the fillets had no influence in composition, but caused a variation in their area and thickness. The largest fillets were with skin, belonging to class C3.

Defumação da tilápia do Nilo (Oreochromis niloticus) inteira eviscerada e filé: aspectos referentes às características organolépticas, composição centesimal e perdas ocorridas no processamento

The objective of the experiment was to evaluate the smoking process effect of whole eviscerated and fillet of Nile tilapia on the organoleptic characteristics (appearance, aroma, color, flavor, texture, salt content and general acceptance), percent weight loss (PP) and proximate composition. FP1 (whole eviscerated fish, 5 hour smoking) and FP2 (fillet, 4 hour smoking) were compared. Scaled, eviscerated fish, FP1 and fillets cut by only one person, FP2 were submitted to brine (30%) and smoking process. Average yield for FP1 and FP2 was 63.98% and 27.11%, respectively. Average loss weight during smoking for fillet (31.33%) was higher, when compared to whole fish (27.04%). Sensorial analysis showed that whole fish was more accepted, regarding flavor and salt content; however, aroma, color and texture were not different between whole fish and fillet. Smoking process reduced moisture and increased crude protein, lipid and ash contents. Losses were higher for fillet, which presented higher crude protein and lower lipid contents compared to whole fish. It was also verified that fillet flavor can be improved by correcting the brine step.

Efeitos da adição de gesso agrícola à cama aviária sobre o desempenho de frangos de corte

The experiment was conducted to evaluate the effect of agricultural gypsum addition to broiler litter on broiler performance. Four levels of gypsum: G1, G2, G3 and G4 (respectively, 10, 20, 30 and 40% in relation to a control group that used 50 kg of wood scraps) were tested. The gypsum was added at different periods: T1 (when the broiler presented nine days of age) and T2 (the total amount of gypsum was divided in half and applied, respectively, at the 9 and 23 days of the broiler ages). A completely randomized design was used, with nine treatments, in a 4 x 2 factorial arrangement (level of gypsum x broiler ages) + control group. Feed intake, weight gain, feed:gain ratio and mortality were evaluated in three periods: from 9 to 21, from 21 to 49, and from 9 to 49 days of the broiler ages. The agricultural gypsum did not affect the broilers performance, except in the feed intake, in the first evaluated period (from 9 to 21 days).

Utilização de dietas úmidas e de rações e água de bebida com edulcorante para leitões desmamados aos 21 dias de idade e efeitos sobre o desenvolvimento histológico e enzimático intestinal

Um experimento foi realizado com leitoes desmamados visando avaliar os efeitos de oito tratamentos, correspondentes a combinacao dos fatores, apresentacoes de racao (seca e umida), tipos de racao (sem e com edulcorante) e tipos de agua de consumo (sem e com edulcorante) sobre o desenvolvimento morfologico e enzimatico intestinal. Foram avaliadas a altura das vilosidades (V), a profundidade das criptas (C) e a relacao altura das vilosidades e profundidade das criptas (V:C) do duodeno e do jejuno, o conteudo de proteina na mucosa do jejuno, e as atividades enzimaticas (UA) da maltase, sacarase e dipeptidase. Utilizaram-se 32 leitoes machos castrados, Large White x Landrace, desmamados aos 21 dias, submetidos aos tratamentos durante oito dias. O delineamento experimental foi em blocos casualizados, com oito tratamentos, fatorial 2 x 2 x 2, com quatro repeticoes. Foram observadas diferencas para a altura das vilosidades do duodeno para os grupos tratados com dieta umida e racao com edulcorante e para a relacao V:C do duodeno para os animais que receberam racao com edulcorante. Houve diferenca para a UA da sacarase e da maltase para os grupos que receberam agua sem edulcorante. As caracteristicas histologicas foram favorecidas pelas dietas umidas, o que pode sugerir que esta apresentacao foi menos agressiva ao trato digestivo. Para os demais fatores os resultados contrariaram as expectativas de que o tratamento agua com edulcorante melhoraria a qualidade do epitelio intestinal. A fase critica pela qual os leitoes foram submetidos, possivelmente, comprometeu os resultados.