Effects of a Novel Consensus Bacterial 6-Phytase Variant on Growth Performance and Bone Ash of Broilers Fed Complex Diets Highly Deficient in Minerals, Digestible Amino Acids and Energy through 42 Days of Age.

An experiment was conducted to evaluate the effects of increasing the dose of a novel consensus bacterial 6-phytase variant expressed in Trichoderma reesei (PhyG) in broilers fed complex diets highly deficient in minerals, dig AA, and energy. Diets were a nutrient-adequate control (PC); a nutrient-reduced control (NC) formulated with a reduction in available P (avP) by 0.199%, Ca by 0.21%, crude protein by 0.72-1.03%, dig Lys by 0.064-0.084%, Na by 0.047%, and ME by 87.8 kcal/kg, respectively; and NC supplemented with PhyG at 500, 1000, and 2000 FTU/kg feed. BW was decreased and FCR increased in the NC vs. PC, while the PhyG treatments were similar to the PC. Carcass yield and bone ash were also maintained with PhyG supplementation. Phytase provided economic benefit on a feed cost per kg of weight basis for 1 to 35 d; the cost reductions equated to USD 0.006, 0.016, and 0.02/kg BWG at 500, 1000, and 2000 FTU/kg. In conclusion, this trial demonstrated that supplementation with a novel consensus phytase variant in diets highly deficient in minerals, dig AA, and energy maintained growth performance and provided economic benefit, with production benefits being maximized at inclusion levels of 2000 FTU/kg.

Differences in fear response strategy and stress susceptibility amongst four different commercial layer strains reared cage free.

Different commercial lines of laying hens may show varying levels of fearfulness in response to stressful events or situations. It is important to understand the differences in fear response and stress susceptibility. In this study, four commercial laying hen lines reared from hatch to 32 weeks of age in a cage free system Strains consisted of a brown egg laying line (Hyline Brown; HB) and three white egg laying lines (W36, W80, and LSL). Sixty hens from each strain were used. Each hen was assessed for fearfulness using the following tests: isolation (ISO), emergence (EMG), inversion (INV), and tonic immobility (TI). Stress was assessed based on physical asymmetry (ASYM), corticosterone (CORT) concentrations, and heterophil:lymphocyte ratio (HL). At 3 weeks of age, the W80 birds exhibited more vocalizations during ISO and a shorter duration to emerge than other lines except the HB birds during EMG. Conversely the W36 birds had fewer vocalizations during ISO and emerged quicker than other birds except the LSL during EMG. At 16 weeks of age, the LSL and the W36 bird demonstrated greater fear in TI than the HB. At 30 weeks of age, the observed fear response strategies of each strain changed from previous age and differences were observed between lines (p < 0.05). At both 16 and 30 weeks of age the HB birds had the highest (p < 0.05) stress indicators (CORT, HL, and ASYM). Furthermore, they had a higher CORT after acute stressor (p < 0.05). Commercial lines of laying hens show clear variation in their stress response strategy and stress susceptibility. Brown egg laying hens tend to actively avoid perceived threats whereas white egg laying hens use passive avoidance. Brown egg laying hens also have higher levels in the measures of stress susceptibility than white egg laying hens. Understanding of individual strain response to fearful stimuli and other stressors is important knowledge to appropriately determine welfare differences between strains of layers as the baseline measures are often different.

Experimental monochromatic light-emitting diode fixture impacts Pekin duck stress and eye development.

Poultry color perception of artificial light-emitting diode (LED) lighting mediates bird physiology and behavior; however, very limited research has focused on how changes in LED light color affect these same parameters in Pekin ducks. Therefore, the objective of this investigation was to determine how four LED bulbs emitting various portions of the visible light spectrum - monochromatic blue (BLUE), monochromatic green (GREEN), monochromatic red (RED), and white (WHITE) - impact the stress, fear responses, eye development, and growth of 768 straight run Pekin ducks. Elevated plasma corticosterone concentration and heterophil to lymphocyte ratio was observed in BLUE and RED ducks compared to WHITE and GREEN ducks (P = 0.005 and P = 0.001, respectively), and asymmetry scores were highest in BLUE ducks (P < 0.001), indicating BLUE and RED lighting increase the stress susceptibility of Pekin ducks. Eye weight was lowest in BLUE and RED ducks compared to GREEN and WHITE ducks (P < 0.01). No differences were observed in d 35 body weight, FCR, gait score, or fear response parameters (P > 0.05). These results indicate BLUE and RED lighting may not be adequate for Pekin duck growout, and Pekin ducks may require artificial light sources containing a broad range of wavelengths, as seen with WHITE and GREEN lights, rather than lights containing more concentrated ranges such as in RED and BLUE lights, but further investigation is needed to understand how eye weight affects duck light perception and welfare. The current findings emphasize that although Pekin ducks and chickens are both sensitive to light color, species-specific nuances in light perception may cause distinct differences in Pekin duck versus broiler physiological responses and must be considered when selecting artificial light color in Pekin duck growout facilities.

Effects of Ultraviolet Light Supplementation on Pekin Duck Production, Behavior, and Welfare.

Ducks, like other domestic poultry species, can visualize the ultraviolet (UV) portion of the light spectrum; however, the importance of UV light radiation in artificially lit duck growout facilities remains unknown. The objective of this study was to determine the effects of UV light supplementation on Pekin duck production parameters, eye development, stress, and fear. Pekin ducks were reared with light-emitting diode (LED) lights supplemented with UV light or just LED lights (control). There were no differences in body weight (p = 0.32), feed conversion ratio (p = 0.38), or gait score (p = 0.89). Differences in eye morphology were observed, with ducks reared under UV light having narrower (12.3 ± 0.06632 mm; p = 0.010) and lighter (1.46 ± 0.01826 g; p = 0.025) eyes than the control (12.5 ± 0.05583 mm; 1.53 ± 0.02386 g). Ducks reared in UV environments had lower acute and chronic stress susceptibility with lower plasma corticosterone (6317 ± 593.79 pg/mL; p = 0.024), heterophil to lymphocyte ratios (0.43 ± 0.02889; p = 0.035), and composite asymmetry (0.58 ± 0.0298; p = 0.002) than control ducks (9242 ± 1120.7 pg/mL; 0.54 ± 0.04212; 0.76 ± 0.03726 mm, respectively). Ultraviolet ducks had a faster latency for the first head movement during tonic immobility (61.28 ± 9.4863 s, p = 0.026) and required more attempts to induce tonic immobility (1.71 ± 0.07333, p = 0.018) than control ducks (100.7 ± 14.846 s and 1.48 ± 0.06478, respectively). There were no differences in inversion testing (p = 0.91). These results indicate that UV lighting can lower stress and fear responses in Pekin ducks and can therefore increase welfare. Additionally, this study emphasizes the importance of choosing correct artificial lighting for all poultry species.