Construction and evaluation of Clostridium perfringens A recombinant α toxin vaccines.

Avian Necrotic Enteritis (NE) is an acute enterotoxaemia caused by Clostridium perfringens A and C. The control of the disease is based on antibiotics added to animal feed. The ban of this practice by consumer markets, considered the biggest challenge to industrial aviculture, demanded the adoption of other alternatives for its control, among others, immunization with recombinant vaccines. The aim of this work was to produce and evaluate C. perfringens recombinant α toxin (rAT) vaccines adjuvanted with either Al(OH)3 (rAT+Al(OH)3 or recombinant B subunit of the heat-labile enterotoxin of Escherichia coli (rLTB) (rAT+rLTB), and a chimeric protein containing the α toxin fused to rLTB (rLTB-AT). The rAT+Al(OH)3 was innocuous and protected mice against a challenge with native α toxin (sT), and it was immunogenic and did not affect productivity parameters in broilers. The rAT+rLTB showed a dose-protection relationship in mice, while rLTB-AT did not protect mice against sT challenge. The rAT could be an alternative for controlling NE.A Enterite Necrótica Aviar (ENA) é uma enterotoxemia aguda, causada pelos Clostridium perfringens A e C, cujo controle baseia-se na adição de antibióticos na ração. A restrição dessa prática pelo mercado consumidor, que tornou seu controle o maior desafio para o setor avícola, exigiu a adoção de novas estratégias para o controle, entre elas a imunização. Vacinas recombinantes vêm despertando grande interesse entre pesquisadores e empresas do setor. O objetivo deste trabalho foi elaborar vacinas de toxina α recombinante de C. perfringens (rAT) utilizando como adjuvantes Al(OH)3 (rAT+Al(OH)3) e subunidade B recombinante da enterotoxina termolábil de Escherichia coli (rLTB) (rAT+rLTB), e construir e avaliar uma proteína quimérica contendo rAT fusionada a rLTB (rLTB-AT). A rAT+Al(OH)3 foi inócua e protetora contra agressão de toxina α nativa (sT) em camundongos, e imunogênica em frangos de corte, sem afetar a produtividade. A rAT+rLTB demonstrou relação dose-proteção em camundongos, entanto a rLTB-AT não protegeu camundongos contra agressão de sT. A rAT demonstrou ser uma alternativa para controlar a ENA. Palavras-chave: Enterite Necrótica Aviar, Clostridium perfringens A, toxina α recombinante, vacinas

Probióticos em avicultura

Durante os últimos anos, o incremento de toxinfecções alimentares em humanos pela ingestão de produtos avícolas contaminados com bactérias, sugeriu que produtos oriundos de aves portadoras dessas bactérias podem veiculá-las ao consumidor, provocando doenças entéricas em humanos. Essas observações e a restrição, por parte do mercado consumidor, ao uso de antimicrobianos na produção animal, aumentaram o interesse mundial pelos probióticos e, conseqüentemente, o número de pesquisas realizadas. Esta revisão mostra os avanços e a situação em que se encontram os probióticos em relação à indústria avícola

Influência da qualidade da casca do ovo sobre índices de produtividade de um incubatório industrial Influence of the eggshell quality on an industrial hatchery productivity indices

Visando a melhorar a produtividade, muitas empresas do mercado avícola incubam a maioria dos ovos produzidos nas granjas, incluindo aqueles com problemas de casca. Para avaliar as conseqüências dessa prática, foram estudados os índices de produtividade de 6992 ovos das linhagens Ross e Cobb, agrupados em cinco categorias, segundo a integridade e a qualidade da casca e o local de postura: controle, trincados, deformados, trincados lavados e deformados lavados. Determinaram-se índices de fertilidade, eclodibilidade, mortalidade embrionária e contaminação. Os índices de eclodibilidade dos ovos deformados foram menores que os trincados e controle (P0,05). O maior índice de contaminação e de mortalidade embrionária foi nos ovos deformados (24,3% e 45,4%) e deformados lavados (36,1% e 34,0%). Os resultados sugerem que se deve dar preferência ao descarte de ovos deformados, independentemente do lavado e do local de postura quando se procura aumento da eficiência em incubatórios industriais.To increase productivity rates, many industries of the poultry market hatch most of the eggs produced in the farm, including those with damaged shells. Aiming at evaluating the implications of this practice in the productivity of industrial hatcheries, fertility, eclosion, mortality and contamination rates of 6992 eggs from the Ross and Cobb breeds, were studied. The eggs were allocated in five groups: control, crashed, deformed, washed crashed and washed deformed. Eclosion rates were lower in deformed eggs than in crashed and control eggs (P0.05). Contamination and mortality rates increased in deformed (24.3% and 45.4%) and washed deformed eggs (36.1% and 34.0%). The results suggest that deformed eggs should be preferentially eliminated from hatching

Probiotic effect of Pichia pastoris X-33 produced in parboiled rice effluent and YPD medium on broiler chickens.

In a previous paper we showed that the yeast Pichia pastoris X-33 grown in parboiled rice effluent supplemented with glycerol byproduct from the biodiesel industry improved the quality of the effluent. In this paper we show the validation of this yeast (PPE) as probiotic for broilers. Its effect on feed efficiency and immunomodulation was compared with the same yeast grown in yeast peptone dextrose medium (PPY), with Saccharomyces boulardii (SBY) and with the controls fed unsupplemented feed (CON). One-day-old female chicks were vaccinated against infectious bursal disease (IBD) and the titers of anti-IBD antibodies were measured by ELISA. PPE group had the highest mean titres on days 14 and 28 (p<0,05), and at 28 days, 64% of the animals showed seroconvertion. The PPE group also showed the best weight gains at 42 days of age, that, on days 7, 14 and 21 were 19%, 15%, and 8.7% higher, respectively, than the control group. The best feed conversion, 8.2% higher than the control group, was obtained by PPY at 42 days. Histopathological studies did not detect any undesirable effects in the supplemented animals. We concluded that Pichia pastoris X-33 when grown in effluents of the rice parboiling industry supplemented with glycerol byproduct from the biodiesel has probiotic properties for poultry

Mean titers of anti-IBD antibodies by ELISA.

<p>CON: Control; SBY: <i>S</i>. <i>boulardii</i>; PPE: <i>P</i>. <i>pastoris</i> effluent; PPY: <i>P</i>. <i>pastoris</i> YPD. Different letters signify the mean statistical differences on the day (p<0.05).</p

Percentage of positive sera and sera with titers above 1000 of anti-IBD antibodies in chicks vaccinated at one day of age.

<p>Percentage of positive sera and sera with titers above 1000 of anti-IBD antibodies in chicks vaccinated at one day of age.</p

Average weight gain and feed conversion means of groups at 1, 7, 14, 21, 28, 35 and 42 days old.

<p>Average weight gain and feed conversion means of groups at 1, 7, 14, 21, 28, 35 and 42 days old.</p

Probiotic effect of <i>Pichia pastoris</i> X-33 produced in parboiled rice effluent and YPD medium on broiler chickens - Fig 2

<p>Histological study showing normal splenic tissue of groups (a) CON, (b) SBY, (c) PPE and (d) PPY. H&E (0bj 10x).</p

Probiotic effect of <i>Pichia pastoris</i> X-33 produced in parboiled rice effluent and YPD medium on broiler chickens - Fig 3

<p>Histological study showing normal hepatocyte and portal vein of the groups (a) CON, (b) SBY, (c) PPE and (d) PPY. H&E (0bj 10x).</p