Influence of dietary Chlorella vulgaris and carbohydrate-active enzymes on growth performance, meat quality and lipid composition of broiler chickens

Article in pressHerein, we investigated the effect of Chlorella vulgaris as ingredient (10% of incorporation) in broiler diets, supplemented or not with 2 formulations of Carbohydrate-Active enZymes (CAZymes; Rovabio Excel AP and a mixture of recombinant CAZymes, composed by an exo-b-glucosaminidase, an alginate lyase, a peptidoglycan N-acetylmuramic acid deacetylase and a lysozyme), on growth performance, meat quality, fatty acid composition, oxidative stability, and sensory traits. One hundred twenty 1-day-old Ross 308 male birds were randomly assigned to one of the 4 experimental diets (n 5 30): corn-soybean meal–basal diet (control), basal diet with 10% C. vulgaris (CV), CV supplemented with 0.005% of a commercialCAZymecocktail (Rovabio Excel AP), (CV1R), and CV supplemented with 0.01% of a 4- CAZyme mixture previously selected (CV 1 M) during the experimental period lasted from day 21 to day 35. Body weight gain and feed conversion rate of broilers were not affected by C. vulgaris but digesta viscosity increased more than 2-fold (P , 0.001) relative to the control. In addition, neither cooking loss, shear force, juiciness, flavor nor off-flavor was impaired by dietary treatments (P.0.05). By contrast, the dietary C. vulgaris increased tenderness, yellowness (b*) and total carotenoids in breast and thigh meats. However, no additional protective effect against lipid oxidation was observed in meat with the inclusion of microalga. Chlorella vulgaris, independently of CAZymes, had a minor impact on meat fatty acid composition but improved the proportion of some beneficial fatty acids. In summary, our data indicate a slight improvement of broiler meat quality and lipid nutritional value, without impairment of broilers’ growth performance, thus supporting the usefulness of this microalga in poultry diets, up to this high level of incorporation. By contrast, the selected CAZyme mixtures used do not significantly improve the release of microalga nutrients in poultry diets, through the disruption of microalga cell wall, which warrants further researchinfo:eu-repo/semantics/acceptedVersio

Impact of dietary incorporation of Spirulina (Arthrospira platensis) and exogenous enzymes on broiler performance, carcass traits and meat quality

This study assessed the effect of Spirulina (Arthrospira platensis), individually and in combination with exogenous enzymes, on growth performance, carcass traits, and meat quality of broiler chickens. One hundred and twenty Ross 308 male chickens were allocated into 40 battery brooders, with 3 birds per cage, and fed ad libitum a corn-based diet during the first 21 D of the trial. The experimental period lasted from day 21 to 35, during which birds were fed 4 different diets: a corn-soybean basal diet, taken as the control group, a basal diet containing 15% Spirulina (MA), a basal diet containing 15% Spirulina plus 0.005% Rovabio Excel AP (MAR), and a basal diet containing 15% Spirulina plus 0.01% lysozyme (MAL). Body weight gain (P , 0.001) and feed conversion rate (P , 0.001) were improved in control chickens, when compared with those fed with Spirulina. In addition, Spirulina increased the length of duodenum plus jejunum in relation to the other treatment (P , 0.01). Chickens on the MAL diet showed a considerable increase in digesta viscosity (P , 0.05) compared with the control group. Breast and thigh meats from chickens fed with Spirulina, with or without the addition of exogenous enzymes, had higher values of yellowness (b*) (P , 0.001), total carotenoids (P , 0.001), and saturated fatty acids (P , 0.001), whereas n-3 polyunsaturated fatty acid (P , 0.01) and a-tocopherol (P , 0.001) decreased, when compared with the control. In conclusion, the incorporation of 15% Spirulina in broiler diets, individually or combined with exogenous enzymes, reduced birds’ performance through a higher digesta viscosity, which is likely associated with the gelation of microalga indigestible proteins. In addition, cell wall of Spirulina was successfully broken by the addition of lysozyme, but not by Rovabio Excel AP. Therefore, we anticipate that the combination of lysozyme with an exogenous specific peptidase could improve the digestibility of proteins from this microalga and avoid their detrimental gelationinfo:eu-repo/semantics/publishedVersio

Plastic deformation of heterogeneous materials: numerical simulation study

A methodology for determining the local stress-strain curves of heterogeneous specimens is proposed. This methodology resorts to the same type of variables usually obtained in the experimental tensile test with the aid of the digital image correlation technique. This approach was successfully tested for heterogeneous specimens composed by several materials with dissimilar plastic properties

Plastic deformation of heterogeneous materials: numerical simulation study

A methodology for determining the local stress-strain curves of heterogeneous specimens is proposed. This methodology resorts to the same type of variables usually obtained in the experimental tensile test with the aid of the digital image correlation technique. This approach was successfully tested for heterogeneous specimens composed by several materials with dissimilar plastic properties

Numerical prediction of fatigue threshold of metallic materials in vacuum

International audienceThe fatigue threshold is determined experimentally following international standards, but its measurement is laborious and time consuming. This paper proposes a numerical approach to determine the fatigue threshold based on the analysis of the crack tip opening displacement, CTOD, evaluated using the finite element method. It assumes that fatigue crack propagation only occurs with plastic deformation at the crack tip. However, a factor of about two was found between the numerical predictions and experimental results of effective fatigue threshold from literature. This difference was attributed to a different mechanism of fatigue crack growth at relatively low load ranges, resulting from environmental effects at the crack tip. Therefore, the approach proposed is adequate to predict the fatigue threshold in vacuum, which is supposed to be controlled by crack tip plastic deformation

Serum adipokine profile and fatty acid composition of adipose tissues are affected by conjugated linoleic acid and saturated fat diets in obese Zucker rats

Funding: The authors acknowledge Clinica Médica e Diagnóstico Dr Joaquim Chaves (Alge´s, Portugal) for the technical assistance regarding the serum lipids determination. The present study was supported by FCT POCTI/CVT/2002/44 750 and PTDC/CVT/2006/66 114 grants. S. V. M., P. A. L. and S. P. A. are the recipients of FCT individual fellowships SFRH/BD/2005/2256, SFRH/BPD/2005/23 931 and SFRH/ BD/2007/37 793, respectively. S. V. M., P. A. L. and C. M. A. performed the animal experiment, tissue sampling, laboratory work and prepared the manuscript. P. O. R. was responsible for Luminex xMAP analysis. S. P. A. and R. J. B. B. were responsible for fatty acid analysis. R. M. A. P. performed the biochemistry serum profile. S. V. M. and R. J. B. B. performed the statistical analysis. M. F. C. and J. A. M. P. were responsible for interpretation of the results, preparation of the manuscript and design of the study.Conjugated linoleic acid (CLA) has been reported as having body fat lowering properties and the ability to modulate the inflammatory system in several models. In the present study, the effects of CLA added to saturated fat diets, from vegetable and animal origins, on the serum adipokine profile of obese Zucker rats were assessed. In addition, the fatty acid composition of epididymal and retroperitoneal adipose tissues was determined and a principal component analysis (PCA) was used to assess possible relationships between fatty acids and serum metabolites. Atherogenic diets (2% cholesterol) were formulated with palm oil and ovine fat and supplemented or not with 1% of a mixture (1:1) of cis-9, trans-11 and trans-10, cis-12-CLA isomers. CLA-fed animals exhibited lower daily feed intake, final body and liver weights, and hepatic lipids content. Total and LDL-cholesterol levels were increased in CLA-supplemented groups. CLA also promoted higher adiponectin and lower plasminogen activator inhibitor-1 (PAI-1) serum concentrations. In contrast to palm oil diets, ovine fat increased insulin resistance and serum levels of leptin, TNF-α and IL-1β. Epididymal and retroperitoneal adipose tissues had similar deposition of individual fatty acids. The PCA analysis showed that the trans-10, cis-12-CLA isomer was highly associated with adiponectin and PAI-1 levels. Summing up, CLA added to vegetable saturated enriched diets, relative to those from animal origin, seems to improve the serum profile of adipokines and inflammatory markers in obese Zucker rats due to a more favourable fatty acid composition. © 2009 The Authors.publishersversionpublishe