The effect of dietary chitosan oligosaccharides (COS) supplementation on ileal digestibilities of nutrients and performance in broilers was assessed by feeding graded levels (0, 50, 100, 150 mg/kg) of COS. Two thousand four hundred male commercial Avian broilers (1-d-old) were assigned randomly to 5 dietary treatment groups (60 birds per pen with 8 pens per treatment). Diet A was a typical corn- and soybean meal-based diet supplemented with 6 mg/kg of an antibiotic flavomycin (positive control). Diet B was the basal diet without any supplement. Diets C, D, and E were formulated by adding 50, 100, and 150 mg/kg of COS to the basal diet, respectively. On the morning of d 21 and 42, 64 birds (8 per pen with 8 pens per treatment) from the growth trial for each age group were killed by cervical dislocation for determination of the ileal digestibilities of nutrients. Dietary supplementation with COS and antibiotic enhanced (P < 0.05) the ileal digestibilities of DM, Ca, P, CP, and all amino acids (except for alanine in the 21-d-old birds or phenylalanine, glutamate, and glycine for the 42-d-old birds). Feed efficiency was improved (P < 0.05) in response to dietary supplementation of an antibiotic or COS (150 mg/kg for d 1 to 21, and 100 and 150 mg/kg for d 21 to 42). The results demonstrate for the first time to our knowledge that dietary COS supplementation was effective in increasing the ileal digestibilities of nutrients and feed efficiency in broilers. Our findings may explain a beneficial effect of COS on chicken growth performance.

Close white dwarf binaries consisting of a white dwarf and an A-, F-, G-, or K-type main-sequence star, henceforth close WD+AFGK binaries, are ideal systems to understand the nature of type Ia supernovae progenitors and to test binary evolution models. In this work we identify 775 WD+AFGK candidates from TGAS (The Tycho-Gaia Astrometric Solution) and Gaia Data Release 2 (DR2), a well-defined sample of stars with available parallaxes, and we measure radial velocities (RVs) for 275 of them with the aim of identifying close binaries. The RVs have been measured from high-resolution spectra obtained at the Xinglong 2.16 m Telescope and the San Pedro Mártir 2.12 m Telescope and/or from available LAMOST DR6 (low-resolution) and RAVE DR5 (medium-resolution) spectra. We identify 23 WD+AFGK systems displaying more than 3σ RV variation among 151 systems for which the measured values are obtained from different nights. Our WD+AFGK binary sample contains both AFGK dwarfs and giants, with a giant fraction ∼43%. The close binary fractions we determine for the WD+AFGK dwarf and giant samples are ≃24% and ≃15%, respectively. We also determine the stellar parameters (i.e., effective temperature, surface gravity, metallicity, mass, and radius) of the AFGK companions with available high-resolution spectra. The stellar parameter distributions of the AFGK companions that are members of close and wide binary candidates do not show statistically significant differences.

The experiment was conducted to assess the effects of phytase supplementation to diets with two levels of phosphorus (P) on ileal and faecal digestibility of nutrients and phosphorus, calcium, nitrogen and energy balances in growing pigs. Fifteen Landrace × Large White × Chinese Black barrows, with an initial live weight of 22·2 kg fitted with a simple T-cannula at the distal ileum, were randomly allocated to one of the five diet treatments, according to a of cross-over design with two periods. The basal diet was typical of southern Asia with maize/rice and rapeseed/cottonseed meals. A normal (NP, supplemented with 4·8 g/kg of CaHPO4) and a low-P diet (LP, not supplemented with CaHPO4) were formulated. Both of the diets were supplemented with and without Natuphos® Phytase (500 phytase units (FTU) per kg diet). An enzyme hydrolysed casein (EHC) diet (diet 5) was also formulated to determine the flow of the ileal endogenous amino acids (AA). The results showed that both the higher level P treatment and phytase supplementation increased (P < 0·05) the apparent ileal digestibility (AID) of dry matter (DM), organic matter (OM), crude protein (CP) and energy. Phytase supplementation also increased (P < 0·05) the AID of Ca and P. Pigs given the higher level of P or the phytase diet increased apparent faecal digestibility (AFD) of DM, OM and energy. Phytase supplementation reduced (P < 0·01) faecal Ca output and increased (P < 0·05) proportional Ca retention. The higher level of P increased (P < 0·001) total P intake and P retention (P < 0·05) but did not affect the proportion of P retained (P > 0·05). Phytase supplementation did not affect P balance (P > 0·05). Pigs given the higher level P or the phytase diet had reduced (P < 0·05) faecal energy concentration, although there was no affect on urine energy output, digestible energy (DE) and metabolizable energy (ME). However, there were P × phytase effects on DE and ME (P < 0·05). There were no P × phytase effects (P > 0·05) on AID of AA except with isoleucine (P < 0·01). Phytase supplementation increased (P < 0·05) AID of histidine, isoleucine, threonine and glutamine and there was a numeric increase in AID for most of the other AA. There was P × phytase effect on AFD of histidine (P < 0·05), isoleucine (P < 0·05), methionine (P < 0·05) and threonine (P < 0·01). Phytase supplementation increased the AFD of isoleucine (P < 0·05), threonine (P < 0·01) and tended to increase AFD of tyrosine (P < 0·05). The level of MCP affected the AFD of lysine (P < 0·01), threonine (P < 0·05), aspartic acid (P < 0·05). Phytase supplementation increased true ileal digestibility of histidine (P < 0·05), isoleucine (P < 0·001), threonine (P = 0·001), glutamine (P < 0·01), respectively. These results indicate that phytase used in the present study was able to improve the utilization of DM, OM, CP, Ca, P, energy and amino acid in a maize/rice and rapeseed/cottonseed meal based diet and reduce total output of them in manure.