Daily and alternate day supplementation of urea or soybean meal to ruminants consuming low-quality cool-season forage: II. Effects on ruminal fermentation

Five ruminally cannulated steers (initial BW=464 ± 26 kg) consuming low-quality forage (5% CP; 78% NDF; DM basis) were used in an incomplete 5 x 4 Latin square with four 18-d periods to determine the influence of supplemental N source and supplementation frequency (SF) on ruminal fermentation dynamics. Treatments, arranged as a 2 x 2 factorial with a negative control, consisted of urea or soybean meal (SBM) supplements offered daily (D) or alternate days (2D) plus an unsupplemented treatment (CON). Urea supplements were provided to meet 100% of the degradable intake protein requirement while SBM supplements were provided on an isonitrogenous basis. All supplemented treatments received an equal quantity of supplemental N over a 2-d period. Ruminal indigestible acid detergent fiber (IADF) passage rate was increased with supplementation (P ≤ 0.03) on the days when D and 2D supplements were provided, as well as when only D supplements were provided. In contrast, ruminal liquid fill and dilution rate were not affected by supplementation, N source, or SF on the days when D and 2D supplements were provided (P ≥ 0.24). However, when only D supplements were offered, ruminal liquid dilution rate was greater (P=0.03) for SBM supplemented steers compared with cohorts receiving supplemental urea, whereas ruminal liquid fill was greater (P=0.03) for steers fed urea supplements. Nitrogen supplementation increased (P = 0.50). In summary, providing a urea-based supplement, as infrequently as every-other-day, was an effective alternative to a SBM-based supplement in maintaining acceptable ruminal fermentation of steers consuming low-quality, cool-season forage. (C) 2013 Elsevier B.V. All rights reserved.Keywords: Non-protein N, Forage, Urea, Soybean meal, Supplementation frequencyKeywords: Non-protein N, Forage, Urea, Soybean meal, Supplementation frequenc

Characterisation of a Desmosterol Reductase Involved in Phytosterol Dealkylation in the Silkworm, Bombyx mori

Most species of invertebrate animals cannot synthesise sterols de novo and many that feed on plants dealkylate phytosterols (mostly C29 and C28) yielding cholesterol (C27). The final step of this dealkylation pathway involves desmosterol reductase (DHCR24)-catalysed reduction of desmosterol to cholesterol. We now report the molecular characterisation in the silkworm, Bombyx mori, of such a desmosterol reductase involved in production of cholesterol from phytosterol, rather than in de novo synthesis of cholesterol. Phylogenomic analysis of putative desmosterol reductases revealed the occurrence of various clades that allowed for the identification of a strong reductase candidate gene in Bombyx mori (BGIBMGA 005735). Following PCR-based cloning of the cDNA (1.6 kb) and its heterologous expression in Saccharomyces cerevisae, the recombinant protein catalysed reduction of desmosterol to cholesterol in an NADH- and FAD- dependent reaction

Uso Pessoal das Tecnologias no Trabalho: Motivadores e Efeitos à Distração Profissional

Apesar dos inúmeros benefícios que as Tecnologias de Informação (TI) – proporcionam a seus usuários, os efeitos adversos da utilização indiscriminada dos dispositivos tecnológicos pessoais no ambiente de trabalho é um tema pouco explorado. Este estudo analisa os aspectos individuais motivadores do uso particular de Tecnologias de Informação no trabalho e a relação da Distração Digital como um componente significativo sobre a perda de atenção dos profissionais durante a execução de suas atividades. A pesquisa evidencia que os aspectos ligados à dependência tecnológica são as principais causas do Uso Pessoal das Tecnologias no ambiente de trabalho. Entre esses motivadores, a perda do Controle do Impulso de uso da TI é o fator mais significativo ao Uso Pessoal das Tecnologias em ambientes profissionais, comparada a outros fatores analisados. A pesquisa também revela que a Distração Digital provoca significativa perda de concentração dos profissionais e que a Utilização Pessoal da TI no ambiente de trabalho é reflexo direto da redução do Engajamento do profissional no seu trabalho. Além disso, o estudo revela que o uso particular das aplicações que promovem interação social não é subterfúgio dos profissionais que manifestaram fraco Suporte Social dos seus pares no local de atuação profissional

Effet sur le coconnage du ver à soie en Italie du Nord-est provoqué par l'emploi du fenoxicarb sur des pommiers

Action of fenoxicarb on "Non-spinning syndrome" of silkworms in North-Eastern Italy. In 1988 appeared in North-eastern part of Italy the "non-spinning syndrome" of silkworms. It has been experimentally prooved that the incapacity of the silkworm larvae to spin their cocoon and the mortality ofthe A. mellifera brood, were connected with the drift of an agricultural pesticide (Fenoxicarb) having juvenilizing action. The use of this product, commercialisedas INSEGAR®, has been forbidden in Italy since 1991. Fenoxicarb also showed a negative action on other useful insects. The utilisation of fenoxicarb can represent a serious danger for sericiculture, apiculture and general biodiversity in many developing countries

Preferenze alimentari in Bombyx mori: saggi comportamentali

Le larve del baco da seta (Bombyx mori L.) sono strettamente monofaghe, infeudate al gelso (Morus spp.) e legate alla presenza di foglia fresca. I dati presentati riguardano lo studio dell’attrattività da parte di alcuni ceppi del baco da seta (due cinesi, due giapponesi e due poliibridi) nei confronti di diete sostitutive, preparate con diverse percentuali di polvere di foglia di gelso essiccata (da 0% a 40%). Lo scopo è quello di determinare il ceppo/i con le migliori “prestazioni” verso la dieta contenente la minor percentuale di gelso compatibile con lo sviluppo dell’organismo. L’indagine è eseguita su larve in I età in condizioni chimico-fisiche controllate. I valori più alti di affluenza al cibo sono stati raggiunti dai ceppi giapponesi, indipendentemente dalla percentuale di gelso; per gli altri ceppi l’attrattività aumenta proporzionalmente alla quantità di gelso presente. Per meglio comprendere i fattori che possono essere responsabili di questo comportamento, su tre diete (0%, 25% e 40%) è stata eseguita, per ogni ceppo, un’analisi delle traiettorie percorse dalle larve per il raggiungimento della dieta. Lo sviluppo cinematico e geometrico della locomozione dell’organismo sono studiati tramite i seguenti indici: l’indice geometrico, che esprime il rapporto tra la distanza dal punto iniziale al punto finale del percorso (D) e la lunghezza (L) effettiva del tragitto (Ig = D/L), descrivendo la geometria complessiva della traettoria seguita; l’indice cinetico (Ik= L/t), che esprime la velocità media della larva; il tasso di dislocazione (Rd = Ik . Ig = D/t), che esprime il tasso di spostamento teorico dell’organismo indipendentemente dalla geometria della traettoria e dalla velocità effettiva posseduta. I risultati ottenuti indicano che, per quanto concerne l’efficienza geometrica del percorso, non esistono differenze significative tra i vari ceppi. Per quanto riguarda l’indice cinetico sono riscontrate delle differenze significative: in particolare, il ceppo cinese 121 risulta più veloce quanto più è bassa la percentuale di gelso, mentre il ceppo giapponese 71 è tanto più veloce quanto maggiore è la quantità di gelso nella dieta. Gli altri ceppi mostrano un comportamento intermedio. In conclusione, si può affermare che il sistema di analisi applicato in questo studio è in grado di fornire indicazioni utili per la scelta del ceppo e della percentuale di gelso idonei per l’allevamento del baco da seta con dieta sostitutiva

Modification of the nutritional parameters and of midgut biochemical and absorptive functions induced by the IGR fenoxycarb in Bombyx mori larvae

Fifth instar larvae of B. mori were topically or orally treated with increasing amounts of the Insect Growth Regulator (IGR) fenoxycarb in a single application, in order to determine its effects on the nutritional parameters, the midgut functional activities and the growth of the silk glands. The IGR affected in a dose-dependent manner the progress of the life cycle of the insect, causing a delay or inhibition of spinning, alteration of the feeding behaviour, decrease of the nutritional parameters, impairment of the growth of the silk glands, and an increased mortality during larval-pupal transformation. Measurement of leucine uptake into midgut brush border membrane vesicles and midgut histochemistry revealed a reduced absorption of leucine by the midgut and a large alteration of a number of midgut enzyme activities as a result of treatments with a high dose of fenoxycarb (2.5 micro g). Treatments with a dose of 2.5 femto g/larva caused an increase in leucine uptake by the midgut, an increased weight of the cocoon shell, and a modification of some midgut enzyme activities. The lepidopteran midgut appears to be a larval organ that responds promptly to the exposure to fenoxycarb. The epithelial columnar cells modify their absorptive functions, at least with regard to amino acid uptake, as well as their metabolic activity, with a modification of the oxidative status of the cells that is detectable with a single dose of the chemical as low as few fg/larva