Effect of phytase in laying hen diets with different phosphorus sources

An experiment was conducted to evaluate the effects of the enzyme phytase in diets formulated with different phosphorus sources on performance, eggshell quality and excretion of commercial laying hens. Two hundred and eighty-eight commercial Hyssex Brown laying hens were evaluated during two production phases, which included eight twenty-eight-day cycles, using a completely randomized design in a 3x2 factorial with six replicates of eight birds per treatment. Three phosphorus sources (calcium and sodium phosphate, micro-granulated dicalcium phosphate and triple super phosphate) and two phytase levels (0 or 1000 FTU/kg diet) were tested in the composition of the diets. After the post-peak period, triple super phosphate decreased bird performance and eggshell quality. It was possible to reduce the levels of phosphorus supplementation when phytase was added to the diet. Besides, phytase supplementation reduced phosphorus, calcium and nitrogen excretions, but affected mean egg weight at production peak.

Apparent absorption of zinc from supplemental inorganic and organic sources to Nile tilapia Oreochromis niloticus juveniles

Nile tilapia Oreochromis niloticus fingerlings were fed with purified or practical diets, supplemented with 150 Ing Zn/kg, from different sources. Dry matter (DM), crude protein (CP), ether extract (EE), and gross energy (GE) apparent digestibility coefficients (ADC), as well as zinc, copper, calcium, and phosphorus apparent absorption coefficients (AAC) were determined by the addition of 0.1% chromic oxide to the diets. The supplemental zinc sources utilized were commercial grade zinc sulfate monohydrate (ZnSO 4), zinc oxide (ZnO) and a zinc amino acid complex (Zn-AA). Analytical grade zinc sulfate heptahydrate was also utilized as a standard reference zinc source. There was a significant difference between purified (74.9%) and practical (41.3%) zinc AAC for the ZnO supplemented diets (P < 0.05). The supplemental zinc sources presented similar AAC when purified diets were utilized. However, ZnSO 4 was the best supplemental zinc source when practical type diets were used. There were no significant differences between supplemental zinc AAC from ZnS0 4 (68.9%), and supplemental zinc AAC from Zn-AA (61.3%) in practical diets, but Zn-AA diet showed a statistically lower zinc AAC when compared with the standard zinc source diet (75.6%). The practical diet supplemented with ZnO had the worst supplemental zinc AAC (41.3%). Dietary copper (74.21%), calcium (70.9%), and phosphorus (71.9%) AAC of the practical diets supplemented with ZnO were statistically lower (P < 0.05) than the respective AAC of the practical ZnSO 4 supplemented diets (83.6%, 84.1%, 87.1%).The ADC of the practical ZnO supplemented diet for DM (76.3%), CP (88.6%), EE (82.4%), and GE (81.6%) were statiscally lower than the respective ADC of the ZnSO 4 practical diet (86.0, 92.7, 93.6, 89.6%, respectively) and those ADC of the Zn-AA practical diet (84.7, 92.7, 93.7, 88.2%, respectively) (P < 0.05). Hence, these results indicate that ZnSO 4 and Zn-AA have equivalent intestinal absorption as supplemental zinc sources for Nile tilapia juveniles and both are superior to ZnO. © Copyright by the World Aquaculture Society 2005.

Sources of omega-6 fatty acids do not alter the rumen degradation and transit of fibre from dairy cow diets

The objective of this study was to evaluate the behaviour of fibre in the digestive tract on the basis of the passage kinetics of forage and concentrate particles in cows fed different omega-6 fatty-acid sources. The scientific hypothesis of this study was that omega-6 fatty acids do not interfere with the digestion of fibre in the diets of dairy cows. Five primiparous lactating Holstein cows were used in the experiment. The experimental diets were: control (C), ground soyabean (GS), cottonseed (CS), soyabean oil (SO), calcium salts of fatty acids (CSFA). The global mean estimates for the parameters of passage rate (gamma) were 0.038 and 0.055 h(-1) for forage and concentrate, respectively. The only significant effect with respect to the passage rate was a high negative correlation between the concentrate passage rate and dry matter intake. There was less undegradable neutral detergent fibre (NDF) in treatments without added lipid. Dietary supplementation with lipid sources does not alter the kinetic parameters of roughage and concentrate particle passage or in vitro NDF degradation. Sources of omega-6 fatty acids do not alter the rumen degradation and transit of fibre.

The effect of lipid sources on intake, rumen fermentation parameters and microbial protein synthesis in Nellore steers supplemented with glycerol

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fibrolytic enzyme production of Myceliophthora thermophila M.7.7. using inexpensive carbon sources and mineral nutrients

This study investigated the effect of inexpensive carbon and nitrogen sources on enzyme production by Myceliophthora thermophila M.7.7 in solid-state fermentation. Three kinds of lignocellulosic waste (corn straw, sugarcane bagasse and sugarcane straw) and six nitrogen sources (urea, calcium nitrate, analytical ammonium sulphate, yeast extract, agricultural fertilizer NPK 20-05-20 and fertilizing grade ammonium sulphate) were tested. Some physical-chermical parameters of the fermentation, such as temperature, initial pH and moisture content of the substrate on enzyme production, were evoluated. The maximum activities of xylanase (446.9 U/ml) endoglucanase (94.7 U/ml) and beta-glucosidase (2.8 U/ml) were observed in a mixture of corn straw and wheat bran (1:1 w/w) as the carbon source using fertilizer grade ammonium sulphate as the nitrogen source. This production occurred for an incubation period of 96 h, at 40°C, with initial moisture content of 70% and pH 5.0. These results have significant interest since they could be used for the future production of enzymes in a low-cost industrial process.

Fatty acid composition of the longissimus dorsi muscle in crossbred steers fed different sources of fatty acids

The objective of this study was to evaluate the fatty acid composition of the longissimus dorsi muscle in carcasses of 3/4 Bos taurus taurus 1/4 Bos taurus indicus steers fed different sources of fatty acids. Thirty-six steers aged 14 months, with a mean live weight of 320 kg, were fed the following diets for 96 days:1) control diet, containing no supplemental fat source; 2) CaSFA, diet containing 50 g calcium salts of fatty acids per kg total dry matter; 3) CS diet, containing 210 g cottonseed per kg total dry matter. The fatty acid composition of the longissimus dorsi muscle was determined by gas chromatography. No difference in slaughter weight, carcass weight, backfat thickness, or longissimus dorsi muscle area was observed between animals receiving the diets CaSFA and CS. Animals consuming the two fat-supplemented diets presented higher concentrations of oleic (C18:1), palmitic (C16:0) and stearic (C18:0) acids, corresponding to an average 80.76% of total fatty acids, and higher concentrations of vaccenic acid (C18:1 t11) in the muscle when compared with the control group. Supplementation of the diet of feedlot crossbred steers with CaSFA or cottonseed did not promote significant alterations in the lipid composition of the longissimus dorsi muscle.

Eocene sedimentary calcium carbonate contents and stable isotope composition of benthic foraminifera

'Hyperthermals' are intervals of rapid, pronounced global warming known from six episodes within the Palaeocene and Eocene epochs (~65-34 million years (Myr) ago) (Zachos et al., 2005, doi:10.1126/science.1109004; 2008, doi:10.1038/nature06588; Roehl et al., 2007, doi:10.1029/2007GC001784; Thomas et al., 2000; Cramer et al., 2003, doi:10.1029/2003PA000909; Lourens et al., 2005, doi:10.1038/nature03814; Petrizzo, 2005, doi:10.2973/odp.proc.sr.198.102.2005; Sexton et al., 2006, doi:10.1029/2005PA001253; Westerhold et al., 2007, doi:10.1029/2006PA001322; Edgar et al., 2007, doi:10.1038/nature06053; Nicolo et al., 2007, doi:10.1130/G23648A.1; Quillévéré et al., 2008, doi:10.1016/j.epsl.2007.10.040; Stap et al., 2010, doi:10.1130/G30777.1). The most extreme hyperthermal was the 170 thousand year (kyr) interval (Roehl et al., 2007) of 5-7 °C global warming (Zachos et al., 2008) during the Palaeocene-Eocene Thermal Maximum (PETM, 56 Myr ago). The PETM is widely attributed to massive release of greenhouse gases from buried sedimentary carbon reservoirs (Zachos et al., 2005; 2008; Lourenbs et al., 2005; Nicolo et al., 2007; Dickens et al., 1995, doi:10.1029/95PA02087; Dickens, 2000; 2003, doi:10.1016/S0012-821X(03)00325-X; Panchuk et al., 2008, doi:10.1130/G24474A.1) and other, comparatively modest, hyperthermals have also been linked to the release of sedimentary carbon (Zachos et al., 2008, Lourens et al., 2005; Nicolo et al., 2007; Dickens, 2003; Panchuk et al., 2003). Here we show, using new 2.4-Myr-long Eocene deep ocean records, that the comparatively modest hyperthermals are much more numerous than previously documented, paced by the eccentricity of Earth's orbit and have shorter durations (~40 kyr) and more rapid recovery phases than the PETM. These findings point to the operation of fundamentally different forcing and feedback mechanisms than for the PETM, involving redistribution of carbon among Earth's readily exchangeable surface reservoirs rather than carbon exhumation from, and subsequent burial back into, the sedimentary reservoir. Specifically, we interpret our records to indicate repeated, large-scale releases of dissolved organic carbon (at least 1,600 gigatonnes) from the ocean by ventilation (strengthened oxidation) of the ocean interior. The rapid recovery of the carbon cycle following each Eocene hyperthermal strongly suggests that carbon was resequestered by the ocean, rather than the much slower process of silicate rock weathering proposed for the PETM (Zachos et al., 2005; 2003). Our findings suggest that these pronounced climate warming events were driven not by repeated releases of carbon from buried sedimentary sources (Zachos et al., 2008, Lourens et al., 2005; Nicolo et al., 2007; Dickens, 2003; Panchuk et al., 2003) but, rather, by patterns of surficial carbon redistribution familiar from younger intervals of Earth history.

Calcium carbonate, organic carbon, d13C and C/N composition of ODP Sites 186-1150 and 186-1151

Past changes in sea-surface productivity in the Oyashio Current are evaluated on the basis of abundances of biological constituents in sediments from Leg 186 sites. Organic carbon contents at Sites 1150 and 1151 are moderate (0.5 to 1.5 wt%) and have an algal origin as indicated by low C/N ratios (<10) and by carbon isotopic compositions ranging from -23.4 to -21.3. A decreasing trend in organic carbon contents, carbon isotope ratios, and C/N ratios occurs with depth at both sites, probably as a consequence of diagenetic degradation of organic matter. Mass accumulation rates (MARs) determined for organic carbon and carbonates at Sites 1150 and 1151 show an abrupt increase between ~5 and 7 Ma. Similar results have been reported for sites in the Indian Ocean and the Pacific Ocean for the same time interval. As it has been previously suggested, the observed increase in MAR for both carbonate and organic carbon at Leg 186 sites probably resulted from augmented nutrient supply either from continental sources or from a more vigorous ocean circulation.

Subdivisions of the sediment column, carbon and calcium carbonate at DSDP Hole 64-480

We analyzed 580 integrated scrape-samples from HPC Site 480 for organic and carbonate carbon. Once precise dating is available, these will provide a high-resolution framework for understanding late Quaternary Oceanographic and climatic fluctuations in this region. Organic carbon ranges mostly within a narrow band of 1.8 to 3.5% C. Calcium carbonate varies from undetectable to over 20%, with an average of only about 5%. Source of carbonate are mostly benthic and planktonic foraminifers, although some sections are dominated by diagenetic carbonate, shelly hash, or nannofossils. Detrital sources are low in carbonate. We divided the sequence into 17 calcium carbonate (CC) zones to separate pulses, low and median values. The CC-Zones show various second-order patterns of cyclicity, asymmetry, and events. Laminated zones have lowest uniform values, but a perfect correlation between carbonate content and homogeneous or laminated facies was not found. Maximum values tend to be located near the transition of these two sediment types, showing that accumulation of carbonate is favored during times of breakdown of stable Oceanographic conditions.

Calcium and sodium concentrations of the Talos Dome ice core, Antarctica

In this study we report on new non-sea salt calcium (nssCa2+, mineral dust proxy) and sea salt sodium (ssNa+, sea ice proxy) records along the East Antarctic Talos Dome deep ice core in centennial resolution reaching back 150 thousand years (ka) before present. During glacial conditions nssCa2+ fluxes in Talos Dome are strongly related to temperature as has been observed before in other deep Antarctic ice core records, and has been associated with synchronous changes in the main source region (southern South America) during climate variations in the last glacial. However, during warmer climate conditions Talos Dome mineral dust input is clearly elevated compared to other records mainly due to the contribution of additional local dust sources in the Ross Sea area. Based on a simple transport model, we compare nssCa2+ fluxes of different East Antarctic ice cores. From this multi-site comparison we conclude that changes in transport efficiency or atmospheric lifetime of dust particles do have a minor effect compared to source strength changes on the large-scale concentration changes observed in Antarctic ice cores during climate variations of the past 150 ka. Our transport model applied on ice core data is further validated by climate model data. The availability of multiple East Antarctic nssCa2+ records also allows for a revision of a former estimate on the atmospheric CO2 sensitivity to reduced dust induced iron fertilisation in the Southern Ocean during the transition from the Last Glacial Maximum to the Holocene (T1). While a former estimate based on the EPICA Dome C (EDC) record only suggested 20 ppm, we find that reduced dust induced iron fertilisation in the Southern Ocean may be responsible for up to 40 ppm of the total atmospheric CO2 increase during T1. During the last interglacial, ssNa+ levels of EDC and EPICA Dronning Maud Land (EDML) are only half of the Holocene levels, in line with higher temperatures during that period, indicating much reduced sea ice extent in the Atlantic as well as the Indian Ocean sector of the Southern Ocean. In contrast, Holocene ssNa+ flux in Talos Dome is about the same as during the last interglacial, indicating that there was similar ice cover present in the Ross Sea area during MIS 5.5 as during the Holocene.