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 α-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 gelation.

Effect of reduced dietary protein and supplementation with a docosahexaenoic acid product on broiler performance and meat quality.

1. Chicken breast meat is a lean meat due to its low content of intramuscular fat (IMF) resulting in an overall lower acceptability by consumers due to a decrease in juiciness, flavour and increased chewiness. Recently, studies performed in pigs suggested the possibility of increasing IMF by decreasing dietary crude protein (CP) content, an effect possibly mediated through an increased lipogenesis. 2. Dietary supplementation with lipids rich in omega 3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) may modulate an increase in the content of these fatty acids in meat from monogastric animals and, thus, promote the daily intake of n-3 LC-PUFA by humans. 3. LC-PUFA are very susceptible to oxidation, resulting in off-flavours that affect meat quality and consumers' acceptability. 4. This trial was conducted to assess the effect of reducing dietary CP, from 21% to 17%, on chicken's meat IMF content and, simultaneously, to evaluate if a complementary supplementation with a proprietary n-3 LC-PUFA source (DHA Gold™) could improve meat quality. These effects were assessed by measuring productive performance and meat quality, oxidative stability, sensory traits and fatty acid profile. 5. A reduction in CP content of broiler diets, from 21% to 17%, balanced for lysine, improved performance while it was not sufficient to increase IMF content in chicken meat. In contrast, DHA Gold™ supplementation had a positive impact both in broiler productive parameters and in meat fatty acid profile. 6. In addition, incorporation of 7.4% of DHA Gold™ in the diet promoted carcass yield but negatively affected chicken meat acceptability by consumers, due to a decrease of meat oxidative stability. 7. Overall the data suggest that neither a dietary supplementation with DHA Gold™ nor a reduction in CP have a direct positive effect in the levels of IMF present in broiler meat.

Contrasting cellularity on fat deposition in the subcutaneous adipose tissue and longissimus lumborum muscle from lean and fat pigs under dietary protein reduction.

The production of pork with high amounts of intramuscular fat (IMF) without an increase in subcutaneous fat is highly desirable for the pig industry and consumers. Herein, we question the impact of dietary protein reduction (18% v. 13%) on fat deposition in the subcutaneous adipose tissue (SAT) and longissimus lumborum (LL) muscle using genetically diverse pigs for body fatness (lean v. fat). A clear effect of genotype was observed on plasma insulin (P=0.004) and leptin (P<0.001), as well as on backfat thickness (P<0.001), with the fat pigs having higher values. Accordingly, IMF was higher in the fat pigs, when compared with their lean counterparts (P=0.003), which was supported by enlarged adipocytes (P<0.001). The area of lipid droplets within the LL fibres (P=0.039) and extramyocellular lipids number (P=0.017) were increased in pigs fed reduced protein diets, regardless of genotype, which is consistent with higher levels of plasma triacylglycerols (P=0.002). The gene-expression pattern of lipogenic factors in the SAT was distinct from the LL muscle. In the SAT, PPARG expression was similar among genotypes (P>0.05), whereas in the LL muscle it was higher in the lean pigs (P=0.023), especially when fed on low protein diet (P=0.057). The CEBPA and FABP4 mRNA levels were increased in the SAT of fat pigs (P<0.001), without changes in the LL muscle (P>0.05). The influence of diet on FABP4 expression in the SAT was dependent on pig's genetic background (P=0.005). In conclusion, fat deposition was clearly influenced by genotype and, to a lesser extent, by dietary protein level, the SAT being more sensitive than the LL muscle. One can speculate that the pathways involved in lipid metabolism are downregulated in intramuscular adipocytes when compared with SAT fat cells. This result might be a direct consequence of the relatively low proportion of adipocytes found in the LL muscle.

New applications for bismuth(III) salts in organic synthesis: from bulk chemicals to steroid and terpene chemistry.

Bismuth(III) salts are currently considered efficient and "ecofriendly" reagents and catalysts for the development of new applications in organic synthesis. The preparation of bismuth(III) triflate and its analogues is reviewed as well as some of their applications to the synthesis of bulk chemicals via electrophilic addition and cyclization reactions. The use of bismuth(III) salts in the development of new chemical processes involving steroids and terpenes as substrates is also discussed.

3-Oxo-18α-olean-28,13ß-olide.

The title terpene, C(30)H(46)O(3), is a 28,13ß-lactone of oleanolic acid prepared with bis-muth trifluoro-methane-sulfonate (OTf), Bi(OTf)(3)·xH(2)O. All rings are trans-fused. The X-ray study shows the inversion of the orientation of 18-H in the lactonization reaction. A quantum chemical ab-initio Roothaan Hartree-Fock calculation of the equilibrium geometry of the isolated mol-ecule gives values for bond lengths and valency angles in close agreement with experimental values. The calculation also reproduces the observed mol-ecular conformation, with puckering parameters that agree well with those determined from the crystallographic study.

6beta-Hydroxy-5beta-methyl-20-oxo-19-norpregn-9(10)-en-3beta-yl acetate.

In the title compound, C(23)H(34)O(4), which is an intermediate in the synthesis of pregnane derivatives with a modified skeleton that show potent abortion-inducing activity, the conformation of ring B is close to half-chair due to the presence of both the C=C double bond and the axial 5beta-methyl group. Rings A and C have conformations close to chair, while ring D has a twisted conformation around the bridgehead C-C bond. Molecules are hydrogen bonded via the hydroxyl and acetoxy groups into infinite chains. Quantum-mechanical ab initio Roothan Hartree-Fock calculations show that crystal packing might be responsible for the low values of the angles between rings A and B, and between ring A and rings C and D, as well as for a different steric position of the methyl ketone side chain compared to the geometry of the free molecule.

19ß,28-Ep-oxy-18α-olean-3ß-ol.

The title triterpene, C(30)H(50)O(2), is an 18α-oleanane derivative prepared by the Wagner-Meerwein rearrangement of betulin with Bi(OTf)(3).xH(2)O (OTF is trifluoromethanesulfonate). There are two symmetry-independent mol-ecules in the asymmetric unit that show no significant differences concerning bond lengths and angles. The conformation of the six-membered rings is close to a chair form, while the five-membered epoxide rings adopt envelope conformations. All rings are trans-fused. In the crystal, mol-ecules are held together by O-H⋯O hydrogen bonds. A quantum-mechanical ab initio Roothan Hartree-Fock calculation on the isolated mol-ecule gives values for bond lengths and valency angles close to the experimental values. The calculations also reproduce well the mol-ecular conformation with calculated puckering parameters that match well the observed values.

16α,17α-Ep-oxy-5α-hydr-oxy-6ß-nitrooxy-20-oxopregnan-3ß-yl acetate.

The title steroid, C(23)H(33)NO(8), is a pregnane derivative obtained regio-, stereo- and chemoselectively from the ring opening of the corresponding 5α,6α;16α,17α-diepoxide with bis-muth(III) nitrate. There are two symmetry-independent mol-ecules in the asymmetric unit that show no significant differences concerning bond lengths and angles. All rings are trans-fused. The conformations of the six-membered rings are close to chair forms, while the five-membered ring adopts an envelope conformation. The mol-ecules are held together by an extensive O-H⋯O hydrogen-bonding network of chains runnning along the a axis.

6ß-Acetamido-5α-hydroxy-cholestan-3ß-yl acetate.

The title steroid, C(31)H(53)NO(4), was prepared from the corresponding 5α,6α-epoxy-cholestane. The conformation of the six-membered rings is close to a chair form, while the five-membered ring adopts a twist conformation. The hydroxyl and acetamide groups are in axial positions. The nucleophilic species bound to the steroid nucleus at position 6 by the ß-face, whereas the hydroxyl group at position 5 has α-orientation. All rings are trans-fused. The crystal packing shows that the mol-ecules related by twofold symmetry exist as O-H⋯O hydrogen-bonded dimers.