Four subsamples of meat and bone meal (MBM) were heated (150 degrees C) for 0, 1.5, 3 and 5 h and then incorporated into four individual diets (100 g MBM/kg diet). The diets were precision-fed to 10 caecectomised and 10 intact adult cockerels. The apparent amino acid digestibility (ApAAD) and true amino acid digestibility (TAAD) of the diets were determined by analysis of the excreta. The digestibility coefficients measured using caecectomised birds were lower than those determined with intact birds. Coefficients of digestibility were statistically examined by analysis of variance for the effects of bird type (caecectomised or intact), type of calculation (apparent or true) and diet (heat-treatment) with and without accommodation for individual bird variability. If individual bird variability was not considered in the analysis the bird type X diet interactions (P less than 0.01) included glutamic acid, tyrosine and serine. When individual bird variability was included in the analysis, significant (P less than 0.01) bird type X diet interactions occurred for aspartic acid, serine, glutamic acid, leucine, tyrosine and lysine and the precision of the data was markedly improved. Amino acid digestibility using the precision-feeding procedure is affected by the selection of either intact or caecectomised birds.
Meat-and-bone meal (MBM), which had been heated (150 degrees C) for 0, 1.5, 3 or 5 h, was used along with an indigestible marker in four diets which were fed to young growing chickens and adult cockerels fitted with ileal cannulae. The ileal digesta from each group of birds were sampled and the apparent amino acid digestibilities of the four diets containing MBM were determined. The apparent digestibility values from growing chickens were higher (P less than 0.05) than those from cannulated cockerels. Differences in apparent digestibility of amino acids between diets as a result of heat treatment were consistent for all amino acids when comparing both techniques, with the exception of glutamic acid and arginine.
ABSTRACT. The cell and culture viability of concentrates of the microalga Nannochloropsis oculata were assessed after storage for a period of 16 weeks at -18, 0 and 5ºC. The concentrates were obtained from the crop of N. oculata, which was harvested at the start of the seasonal growth period using a process of flocculation. Flocotac Plus was used as the flocculation agent, achieving flocculation of 90% of the suspended microalgae. It was observed that the chemical process did not affect the number of live cells. The concentrate stored at -18ºC presented slow freezing, which deteriorated the cells and therefore reduced cell viability after five weeks (75%). The concentrates stored at 0 and 5ºC showed cell viability over 97% after the 16 weeks. Culture viability was only seen in the concentrates stored at 0 and 5ºC, which showed specific growth rates similar to those of the control culture. It may be concluded that it is possible to use flocculates stored at 0 and 5ºC after 16 weeks as inoculum for mass crops of N. oculata for food, green water and other uses. Keywords: Nannochloropsis oculata, shelf-life, flocculation, cell viability, aquaculture.Evaluación de la vida útil de floculados de Nannochloropsis oculata almacenados a distintas temperaturas de conservación RESUMEN. Se evaluó la viabilidad celular y de cultivo de concentrados de microalga Nannochloropsis oculata, almacenada durante 16 semanas a -18, 0 y 5ºC. El concentrado se obtuvo de un cultivo de N. oculata, cosechado al inicio de la fase estacionaria de crecimiento, mediante un proceso de floculación. Como agente floculante se empleó Flocotac Plus, con el cual se logró una floculación del 90% de las microalgas suspendidas y el proceso químico no afectó el número de células vivas. El concentrado almacenado a -18ºC experimentó un proceso de congelación lenta que deterioró las células y por ello redujo su viabilidad celular a cinco semanas (75%). Los concentrados almacenados a 0 y 5ºC mostraron viabilidad celular superior al 97% al cabo de 16 semanas. Se observó viabilidad del cultivo sólo en los concentrados almacenados a 0 y 5ºC, que presentaron tasas de crecimiento específico similares a las tasas del cultivo control. Se concluye que es posible utilizar, después de 16 semanas, floculados almacenados a 0 y 5ºC como inóculo de cultivos masivos de N. oculata para alimento, aguas verdes y otros usos.
1. Three subsamples of a batch of meat and bone meal (MBM0) were heated at 150 degrees C for 1.5 h (MBM1.5), 3 h (MBM3) or 5 h (MBM5). 2. The MBM's were included in 4 wheat-gluten based diets, each limiting in lysine. 3. The lysine digestibility for each of the diets was determined using precision-fed intact adult cockerels and caecectomised adult cockerels, ileal cannulated adult cockerels, the ileal digesta and excreta of young growing chickens. 4. The results of the digestibility assays were compared with the relative amount of lysine available as determined by growth assay. 5. Comparison of the regression lines of digestible lysine (determined with the digestibility assays) on available lysine (determined by growth assay) indicated that while the magnitude of the digestibility values varied significantly (P less than 0.05) depending on the type of assay used, the differences in lysine digestibility as a result of heat treatment across the 4 diets was the same when comparing assays (the regression lines were parallel). 6. The results of each digestibility assay also correlated with relative digestibility values determined by growth.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.