Nutritional characteristics of meat from lambs fed diets containing mulberry hay

The objective of this study was to evaluate the nutritional characteristics of meat from lambs fed diets containing 0%, 12.5% and 25.0% (dry matter (DM)) mulberry hay as a substitute for the concentrate. Twenty-four feedlot Île-de-France lambs with an average age of 60 days and bodyweight (BW) of 15 kg were fed in individual stalls and slaughtered at 32 kg BW, at approximately 130 days old. The chemical composition of the experimental diets contained, respectively, 584.4, 569.4 and 571.8 g DM/kg; 188.8, 185.1 and 184 g crude protein (CP)/kg and 29.9, 29.5 and 25.5 Mcal/kg DM for the mulberry hay inclusion levels of 0%, 12.5% and 25.0%, with a dietary forage to concentrate ratio of 50 : 50. The chemical composition of the meat was 757.9 g moisture/kg DM, 208.6 g CP/kg DM, 22.9 g crude fat/kg DM and 10.5 g ash/kg DM. Cholesterol concentration (36.07 mg/100 g) in the meat was not influenced by mulberry hay inclusion of the diet. An increase was observed in the concentrations of saturated pentadecanoic, heptadecanoic and arachidic acids; monounaturated heptadecenoic acid; and polyunsaturated α-linolenic, ɣ-linolenic and eicosapentaenoic acids. Nervonic and conjugated linoleic acid (CLA) concentrations responded quadratically, representing 3.7 g/kg and 5.9 g/kg of the meat when mulberry hay was included at 16.98% and 12.56%. Omega-3 acid concentrations increased, while the omega-3 : omega-6 ratio decreased in the meat of mulberry hay-fed animals. Inclusion of mulberry hay in lamb diets increases the amount of desirable fatty acids in their meat, whose nutritional characteristics are improved.Keywords: Chemical composition, fatty acids, feedlot, sheep mea

Spatial and seasonal contrasts of sedimentary organic matter in floodplain lakes of the central Amazon basin

In this study, we investigated the seasonal andspatial pattern of sedimentary organic matter (SOM) in fivefloodplain lakes of the central Amazon basin (Cabaliana,Janauaca, Canaçari, Mirituba and Curuai) which have differentmorphologies, hydrodynamics and vegetation coverages.Surface sediments were collected in four hydrologicalseasons: low water (LW), rising water (RW), high water(HW) and falling water (FW) in 2009 and 2010.We investigatedcommonly used bulk geochemical tracers such as theC V N ratio and the stable isotopic composition of organic carbon(?13Corg/. These results were compared with lignin phenolparameters as an indicator of vascular plant detritus andbranched glycerol dialkyl glycerol tetraethers (brGDGTs) totrace the input of soil organic matter (OM) from land to theaquatic settings. We also applied the crenarchaeol as an indicatorof aquatic (rivers and lakes) OM. Our data showed thatduring the RW and FW seasons, the surface sediments wereenriched in lignin and brGDGTs in comparison to other seasons.Our study also indicated that floodplain lake sedimentsprimarily consisted of allochthonous, C3 plant-derived OM.However, a downstream increase in C4 macrophyte-derivedOM contribution was observed along the gradient of increasingopen waters – i.e., from upstream to downstream. Accordingly,we attribute the temporal and spatial difference inSOM composition to the hydrological dynamics between thefloodplain lakes and the surrounding flooded forests