Minimal effects of ultraviolet light supplementation on egg production, egg and bone quality, and health during early lay of laying hens.

Chicken vision is sensitive to ultraviolet (UV) light containing the UVA spectrum, while UVB plays a key role in the endogenous production of vitamin D3. However, commercially available light sources are typically deficient in the UV spectrum and thus may not adequately fulfill the lighting requirements of indoor-housed laying hens. We hypothesized that supplementary UVB light may improve egg production and egg quality, and bone health during early lay relative to UVA supplementation or standard control lighting. To investigate the effects of UV light supplementation, an experiment was conducted on 252 ISA Brown hens during 16 to 27 weeks of age. Birds were housed in eighteen pens (14 hens/pen) under three different light treatment groups each with six replications: (i) UVO: standard control lighting with LED white light, (ii) UVA: control lighting plus supplemental daylight with an avian bulb, and (iii) UVA/B: control lighting plus a supplemental full spectrum reptile bulb containing both UVA and UVB wavelengths. Hen-day egg production and egg quality, blood parameters including plasma Ca and P, and serum 25(OH)D3, and hen body weight and external health scoring were measured at different age points; while bone quality was assessed at the end of the experiment at 27 weeks. Data were analyzed in JMP® 16.0 using general linear mixed models with α level set at 0.05. Results showed that UVA and UVA/B supplemented birds reached sexual maturity (50% production) 3 and 1 day earlier, respectively, than control birds. There was a trend for UV lights to increase hen-day egg production (P = 0.06). Among egg quality traits, only eggshell reflectivity and yolk index were affected by UV lights (P = 0.02 and 0.01, respectively); however, most of the egg quality traits changed over age (all P < 0.01). Post-hoc tests showed higher serum 25(OH)D3 in the UVA/B group relative to control hens (P < 0.05); but there was no treatment effect on plasma Ca and P or on bone quality parameters (all P > 0.05). A significant interaction was observed between light treatment and age for the number of comb wounds (P = 0.0004), with the UV supplemented hens showing more comb wounds after 24 weeks. These results demonstrated that supplemental UVA/B light had minimal effects on egg production and egg quality, whereas, UVA/B exposure may increase vitamin D3 synthesis during the early laying period. The optimum duration of exposure and level of intensity needs to be determined to ensure these benefits.

Colour of floral styles in the Banksia spinulosa Sm complex (Proteaceae) relates to the anthocyanin and flavonol profile, not soil pH.

The cylindrical conflorescences of the Banksia spinulosa Sm complex have several different colour types, i.e., black, red, maroon, lemon, and yellow. It is unknown if colour variation is due to extrinsic factors, importantly soil pH. Recent morphological observations have indicated that style colour are not contiguous, so follow-up chemical and soil analysis was conducted to further characterize the colour difference with respect to putative taxa and abiotic factors. Conflorescences of all known colours were sampled from across the eastern Australian distribution of B. spinulosa, and the respective soils were sampled and analysed for pH and total nitrogen. Regression analyses of this data demonstrated that pH and nitrogen gave nil and limited predictability for style colour respectively, i.e., only the taxa with black styles demonstrated a correlation, which was to a soil with slightly higher nitrogen content (p < 0.05). Furthermore, differences of pH were more often between taxa with conflorescences of the same colour. For chemical characterisation, the coloured styles were removed from conflorescences, extracted, and analysed by liquid chromatography-mass spectrometry (HPLC-MS/MS-DAD). Ten anthocyanin and twelve flavonol monoglycosides were identified by mass spectral fragmentation patterns (MS1 and MS2) and retention times. The data demonstrates that style colour differences are caused by the concentration of anthocyanins and their specific chemistry. It remains to be determined if the differences of anthocyanin expression are caused by other abiotic factors, or if it is intrinsic to the respective taxon.

Dietary nitrate and presence of protozoa increase nitrate and nitrite reduction in the rumen of sheep.

Nitrate ( NO 3 - ) supplementation is an effective methane (CH4 ) mitigation strategy for ruminants but may produce nitrite ( NO 2 - ) toxicity. It has been reported that rumen protozoa have greater ability for NO 3 - and NO 2 - reduction than bacteria. It was hypothesised that the absence of ruminal protozoa in sheep may lead to higher NO 2 - accumulation in the rumen and a higher blood methaemoglobin (MetHb) concentration. An in vivo experiment was conducted with defaunated (DEF) and faunated (FAU) sheep supplemented with 1.8% NO 3 - in DM. The effects of rumen protozoa on concentrations of plasma and ruminal NO 3 - and NO 2 - , blood MetHb, ruminal volatile fatty acid (VFA) and ruminal ammonia (NH3 ) were investigated. Subsequently, two in vitro experiments were conducted to determine the contribution of protozoa to NO 3 - and NO 2 - reduction rates in DEF and FAU whole rumen digesta (WRD) and its liquid (LIQ) and solid (SOL) fractions, incubated alone (CON), with the addition of NO 3 - or with the addition of NO 2 - . The results from the in vivo experiment showed no differences in total VFA concentrations, although ruminal NH3 was greater (p < .01) in FAU sheep. Ruminal NO 3 - , NO 2 - and plasma NO 2 - concentrations tended to increase (p < .10) 1.5 hr after feeding in FAU relative to DEF sheep. In vitro results showed that NO 3 - reduction to NH3 was stimulated (p < .01) by incoming NO 3 - in both DEF and FAU relative to CON digesta. However, adding NO 3 - increased (p < .05) the rate of NO 2 - accumulation in the SOL fraction of DEF relative to both fractions of FAU digesta. Results observed in vivo and in vitro suggest that NO 3 - and NO 2 - are more rapidly metabolised in the presence of rumen protozoa. Defaunated sheep may have an increased risk of NO 2 - poisoning due to NO 2 - accumulation in the rumen.

The effects of dietary nitrate on plasma glucose and insulin sensitivity in sheep.

Nitrate (NO3 ¯ ) is an effective non-protein nitrogen source for gut microbes and reduces enteric methane (CH4 ) production in ruminants. Nitrate is reduced to ammonia by rumen bacteria with nitrite (NO2 ¯ ) produced as an intermediate. The absorption of NO2 ¯ can cause methaemoglobinaemia in ruminants. Metabolism of NO3 ¯ and NO2 ¯ in blood and animal tissues forms nitric oxide (NO) which has profound physiological effects in ruminants and has been shown to increase glucose uptake and insulin secretion in rodents and humans. We hypothesized that absorption of small quantities of NO2 ¯ resulting from a low-risk dose of dietary NO3 ¯ will increase insulin sensitivity (SI ) and glucose uptake in sheep. We evaluated the effect of feeding sheep with a diet supplemented with 18 g NO3 ¯ /kg DM or urea (Ur) isonitrogenously to NO3 ¯ , on insulin and glucose dynamics. A glucose tolerance test using an intravenous bolus of 1 ml/kg LW of 24% (w/v) glucose was conducted in twenty sheep, with 10 sheep receiving 1.8% supplementary NO3 ¯ and 10 receiving supplementary urea isonitrogenously to NO3 ¯ . The MINMOD model used plasma glucose and insulin concentrations to estimate basal plasma insulin (Ib ) and basal glucose concentration (Gb ), insulin sensitivity (SI ), glucose effectiveness (SG ), acute insulin response (AIRg) and disposition index (DI). Nitrate supplementation had no effect on Ib (p > .05). The decrease in blood glucose occurred at the same rate in both dietary treatments (SG ; p = .60), and there was no effect of NO3 ¯ on either Gb , SI , AIRg or DI. This experiment found that the insulin dynamics assessed using the MINMOD model were not affected by NO3 ¯ administered to fasted sheep at a low dose of 1.8% NO3 ¯ in the diet.