270 research outputs found

    Effects of early age feed restriction and dietary ascorbic acid on heterophil/lymphocyte and tonic immobility reactions of transported broiler chickens

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    Broiler chickens were subjected to (i) pre-treatment for 24 h with 1,200 ppm L-ascorbic acid in their drinking water on day 42 (AA), (ii) 60% feed restriction on days 4, 5 and 6 (FR), (iii) combination of AA and FR (AAFR), or (iv) neither treatment (control). On day 43, the birds were crated and transported in an open truck for either 60 min or 120 min. Heterophil/ lymphocyte ratios (HLR) were determined prior to (T0) and 20 h following the 60 min (T60) and 120 min (T120) journeys. Prior to transportation, all treatment groups had similar HLR. Following T 60, the AAFR chicks had smaller increase in HLR than their control, AA and FR counterparts. The AA, FR and AAFR birds exhibited lower HLR than controls following T120. The means HLR of AA, FR and AAFR did not differ significantly. Irrespective of journey time, AA and AAFR birds had shorter tonic immobility duration than their FR and control counterparts. The tonic immobility duration of all birds increased with journey duration

    Heterophil / lymphocyte response and performance of feed and water restricted broiler chickens under tropical conditions

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    The effects of restricting feed [60% of ad libitum (AL) intake] (FR) or water provided from 0900 h to 1600 h, daily) (WR) or both (FWR) from 14 to 42 days of age on heterophil/lymphocyte (H/L) response and performance in broiler chickens under the hot humid tropical conditions were determined. Feed and/or water limitation retarded growth, but had no adverse effect on overall feed conversion ratio and survivability. The trend for total feed and water consumption was similar to body weight pattern with AL>WR>FR>FWR. The nutritional regimens had significant effect on overall water:feed ratios with FR>(AL=WR)>FWR. Restriction of feed and/or water resulted in marked elevation of H/L ratios. As measured by H/L ratios, the effect of adapting to FR dissipated between 16 to 21 days after the onset of feed restriction, The H/L ratios of WR and FWR birds remained elevated throughout the duration of the experiment

    The influence of contact with humans on physiological and behavioural responses in commercial broiler chickens and red jungle fowl when reared separately or intermingled

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    This study investigated the effects of regular physical and visual contacts with human beings on bird-to-bird pecking behaviour, tonic immobility (TI) duration, corticosterone, heterophil to lymphocyte ratio (HLR) and growth in commercial broilers (CB) and jungle fowl (JF) raised from hatching as separate and intermingled flocks. On day 0, chicks were randomly assigned to 27 floor pens: nine with CB (20 birds / pen), nine with JF (20 birds / pen) and nine where chicks from the two genotypes were intermingled (10 CB and 10 JF / pen). The following treatments were applied (three pens per treatment) daily from day 1 to 21 to both CB and JF: (1) non-handled controls received no physical or visual contact with humans other than the routine husbandry (control), (2) each chick in the physical contact group were picked up individually, and stroked gently for 30 s once daily (PC), (3) a chick in the visual contact group was randomly caught, picked up and stroked gently for 10 min twice daily (VC). Both PC and VC treatments were done in the chicks’ home pens to allow other birds in the flock to view the procedure. On day 42, CB that were raised as separate flocks had significantly greater body weights than those of intermingled flocks, similarly to CB subjected to PC in comparison with controls and VC. However, the body weights of JF were not affected by flock type or human contact. Intermingling increased bird-to-bird pecking activity in JF, and retarded body weight, elevated plasma levels of corticosterone and HLR in CB. Both PC and VC significantly reduced the incidence of harmful pecking and attenuated HLR and TI reactions in CB. Irrespective of flock type, JF, as measured by TI duration, were significantly more fearful than their CB counterparts. Regular physical contact was more effective than visual contact in ameliorating the TI reaction in JF. Regular human contact may attenuate the expression of bird-to-bird pecking and its harmful consequences

    The Effect Of Sex-Linked Dwarf (Dw), Naked Neck (Na) And Frizzle (F) Genes On Various Traits In Laying Hens Under Tropical Conditions

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    A study was carried out to investigate the effect of the sex-linked dwarf (dw) , naked neck (Na) and frizzle (l) genes on various quantitative traits in layers and also to identify the appropriate genotypes under tropical conditions . The experimental stock comprised of non-dwarf non-frizzled non-naked neck or normal (Dw- ff nana) , naked neck (Dw- ff Nana) , frizzled (Dw- Ff nana) , frizzled naked neck (Dw- Ff Nana) , dwarf (dw- ff nana) , dwarf naked neck (dw- ff Nana) , dwarf frizzled (dw- Ff nana) and dwarf f rizzled naked neck (dw- Ff Nana) genotypes . The dw was observed to cause a profound reduction in body weight , body conformation , egg production and egg weight . However , the dw reduced feed intake and improved feed efficiency . The dw also had detrimental effect on several egg quality traits. Body weight and body conformation measurements were not affected by the Na , while feed intake was significantly increased in both dwarf and non-dwarf populations . The Dw- ff Nana hens were observed to have better egg production and egg weight . Shell quality traits were found to improve due to the Na . However , among the dwarf population , the Na had an adverse effect on feed efficiency

    The relationships between cage floor preferences and performance in broiler chickens

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    Two experiments were conducted with broiler chickens to determine cage floor preferences, the strength of preference for a particular floor type and to evaluate the effect of rearing broilers on the preferred cage floor on productivity. In experiment 1, chicks when offered free access to either wire (WF) or plastic (PF) mesh flooring, preferred the former. However, when the perferred floor type (WF) was illuminated at 800 lux, birds spent longer time on PF. Also provision of incandescent lamps at PF resulted in broilers spending significantly longer period on WF. In experiment 2, while floor type had no effect on growth of female chicks throughout the duration of study, male chicks grown on PF were heavier than their WF counterparts on Days 21, 28, 35 and 42. Neither livability, nor incidence of breast blisters and leg deformities was affected by floor type

    Characteristics and application of the asymmetric slab waveguide in optical integrated circuit

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    In this chapter, consists of demand in optical networking for photonic components that meet performance criteria as well as economic requirements has opened the door for novel technologies capable of high-yield low cost manufacturing while delivering high performance and enabling unique functions. The most promising new technologies are based on integrated optics. Integration permits the parallel production of complex multif unction photonic circuit on asymmetric slab waveguide. This kind of waveguide has very important role for designing the integrated optical circuit. To obtain the high performance function, we need to observe the waveguide characteristic in transverse mode (TE mode and TM m ode), the waveguide structure, and materials. Hence, a thoroughly study on asymmetric slab waveguide is essential in future implementation of optical devices in optical network. Integrated optics is the technology of constructing optic devices and networks on substrates [1]. Integrated optics offers the capability of combining optics and electronic components on a single substrate to produce functional systems or subsystems. Within an integrated optic network, light is transferred between components by a rectangular dielectric-slab waveguide

    Effects of dietary inclusion of palm kernel cake and palm oil, and enzyme supplementation on performance of laying hens.

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    A total of 392 twenty eight week-old laying hens was used to study the effects of dietary inclusion of solvent extracted palm kernel cake (PKC) (0%, 12.5% and 25%) and enzyme (mixture of mannanase, α-galactosidase and protease) supplementation (0 kg/t, 1 kg/t and 2 kg/t) on the performance of laying hens. The levels of PKC did not significantly influence nitrogen corrected true metabolizable energy (TMEn) of the diets. Enzyme supplemented PKC had significantly higher AME and TMEn values than PKC diets with no enzyme supplementation. Dietary inclusion of 12.5% and 25% PKC in the diets of laying hens did not adversely affect mean egg production or daily egg mass. However, layers consumed significantly more PKC-based diets and had significantly poorer feed conversion ratios (FCR) than controls. However, the feed intake and FCR of hens provided the 12.5% PKC-based diets with enzyme supplementation at 1 kg/t did not differ from the controls. Dietary inclusion of PKC or enzyme did not affect eggshell quality, but egg yolk colour was significantly paler when layers were fed the 25% PKC diet

    Power Consumption Modeling and Analysis of Integrated Optical-Wireless Access Network

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    The integration of optical and wireless technologies at access networks are considered as a future solution which provide both high bandwidth and high mobility in an efficient way. GPON is a suitable candidate for optical backhaul due to the combination of higher data rates, greater split ratio and support for triple play services hence it offers maximum flexibility and cost advantages. On the other hand, recent developments of new radio access technologies and introduction of femtocell base stations provide the potential of offering broadband services and applications to everyone and everywhere. However, the power consumption of this network demands a particular attention because access networks are the largest contributor the network related electricity consumption. Therefore, in this paper we evaluate the power consumption of integrated optical-wireless access network which is based on independent ONU-BS architecture. We proposed a power consumption model for such network and the assessment has been done under different simulation scenarios. The constructed model will provide insight of the energy performance of the integrated access network so that in the network design process, focus can be done to the most energy saving strategies

    Dynamic bandwidth allocation algorithm for long reach passive optical network

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    Next generation broadband access networks are gaining more interests from many key players in this field. The demands for longer reach and higher bandwidth are among the driving factors for such network as it can reach wider area up to 100 km, even beyond; has enhanced bandwidth capacity and transmission speed, but with low cost and energy consumption. One promising candidate is long reach passive optical network, a simplified network with reduced number of network elements, equipment interfaces, and even nodes; which leads to a significant reduction in the network’s capital expenditure and operational expenditure. Outcome of an extended reach often results in increased propagation delay of dynamic bandwidth allocation messages exchange between the optical line terminals and optical network units, leading to the degradations of bandwidth allocation and quality of service support. Therefore, an effective bandwidth allocation algorithm with appropriate service interval setup for a long reach network is proposed to ensure the delay is maintained under ITU-T G.987.1 standard requirement. An existing algorithm is improved in terms of service interval so that it can perform well beyond 100 km. Findings show that the improved algorithm can reduce the mean delay of high priority traffic classes for distance up to 140 km
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