Significant Difference In Feeding Research Articles

Impact of Environmental Temperatures on Feed and Water Consumption in Broilers and Layers in Commercial and Backyard Poultry Farms, Maiduguri, Borno State

This study investigates the influence of environmental temperatures on feed intake and water consumption in broilers and layers across commercial and backyard poultry farms in Maiduguri, Borno State. Data were collected over six months from multiple farms, accounting for seasonal variations and management practices. The findings revealed significant differences in feed and water intake between commercial and backyard farms influenced by temperature fluctuations. Specifically, broilers showed higher sensitivity to temperature changes compared to layers. At temperatures below 25°C, broilers in commercial farms consumed significantly more feed (120 ± 0.5g) and less water (250 ± 0.3ml) compared to higher temperatures above 40°C where feed consumption decreased (100 ± 0.3g) and water intake increased (380 ± 0.6ml) (p < 0.05). Layers followed a similar trend with higher feed intake (110 ± 0.5g) at temperatures below 25°C and increased water consumption (350 ± 0.5ml) at temperatures above 40°C (p < 0.05). Comparative analysis indicated that commercial broilers had a significantly higher average feed intake during the rainy season (180 ± 0.5 g/day) compared to backyard broilers (120 ± 0.3 g/day, p < 0.05), with similar patterns observed during the hot dry season. In contrast, backyard broilers consumed more water (350 ± 0.6 ml/day) than commercial broilers (300 ± 0.4 ml/day) during the hot dry season (p < 0.05). These findings suggest that temperature management is crucial for optimizing poultry performance, with implications for different farming systems.

Comparison of two Specialized Cleft Palate Feeders.

To evaluate feeding efficiency and weight gain in infants with cleft palate fed using 1 of the 2 specialty feeders. Retrospective cohort study. Cleft palate clinic in a tertiary pediatric hospital. Infants with cleft palate (with or without cleft lip) fed using the Medela SpecialNeeds® Feeder (n = 39) or the Dr. Brown's® Specialty Feeding System (n = 16) and who had documented feeding and growth data available from the time of initial assessment in the first month of life and at subsequent follow-up between 2 and 4 months. Feeding velocity (mL/min). Calorie velocity (kcal/min), weight gain, and complications associated with poor feeding. No statistically significant differences in feeding or calorie velocities were identified between infants with cleft palate fed with the Medela SpecialNeeds® feeder and those fed with the Dr. Brown's® feeder. Mean weight z-scores by month did not differ significantly between the 2 bottle groups at the time of initial assessment (P = .84) and follow-up (P = .20). Mean weight z-scores by month for the infants included in this study fell below the 50th percentile. The proportion of infants who developed otitis media, reflux requiring treatment, or who required hospital admission for nasogastric (NG) feeds did not differ significantly between the 2 groups. Despite being adequately powered for the primary outcome, no significant differences were identified between infants fed with the Medela or the Dr. Brown's feeders in terms of feeding velocity, calorie velocity, weight gain, or complications.

The association between hunting and the feeding and vigilance times of American bison in North Dakota and Montana

Bison being a keystone species makes understanding the impact that hunting can have on their behavior vital to their ecological recovery. Prior studies have explored the effects of hunting on reproductive behavior and stress levels in ungulates; however, the effects of hunting on feeding and vigilance of American bison (Bison bison) have not yet been explored. We hypothesized that feeding times of bison in the hunted populations would be significantly shorter than that of bison in the nonhunted population and vigilance times would be significantly longer than that of bison in the nonhunted population. We utilized focal animal sampling while observing videos of bison from two hunted populations and one non-hunted population, and the feeding and vigilance times of individual bison were recorded. Notably, we found significant differences in feeding and vigilance times of bison in the hunted and non-hunted populations. However, these differences did not support our original hypothesis; bison in hunted populations spent more time feeding and less time vigilant than bison in the non-hunted population. The results of our study differed from previous investigations of ungulates, however, as noted in prior elk studies, the hunted bison may have fed more and were less vigilant because they encountered periods of safety within the observed times. Future studies investigating the association between hunting and bison behaviors could use populations of bison that are hunted more frequently, which may provide different results.

Observations of the foraging behavior and activity patterns of the Korean wood mouse, Apodemus peninsulae, in China, using infra-red cameras.

Apodemus peninsulae, a dominant rodent species in temperature forests of northeastern China, is a model animal to explore the ecological functions of reciprocal coevolution of animals and plants. From August to October 2016, 24 infra-red cameras were installed to study the feeding behavior and activity patterns of A. peninsulae in its natural environment. By analyzing 5618 video records, we found that feeding behavior, followed by motor and sentinel behaviors, was their main activity. In the behavior spectra, motor behavior (creep, walk, and skip), feeding behavior (forage, feeding, transport, hoarding, and clean), and sentinel behavior (alert, flee, banishment, and coexistence) accounted for 57.96%, 40.36%, and 1.68% of their behavior, respectively. The peak of feeding behavior occurred between 18:00 and 23:00, and feeding behavior frequency, duration, and activity rhythms differ among August to October. Furthermore, activity was the greatest after sunset and before sunrise, indicating a nocturnal lifestyle; however, from August to October, the start time of the activity was earlier, and the end time was later than usual. On average, mice spent 21.6 ± 11.6 times/night feeding, with a duration of 63.58 ± 98.36 s; while they spent less time in foraging, 39.05 ± 51.63 s. We found a significant difference in feeding and foraging frequency, with mice spending on average 10.84 ± 9.85 times/night and 9.23 ± 11.17 times/night, respectively. Our results show that feeding and foraging behavior is also influenced by light intensity, suggesting a preference for crepuscular periods of the day. Infra-red cameras are very useful in detecting activity patterns of animals that are not easily observable; these cameras are able to capture a large amount of valuable information for research into ecological functions.

Ex-situ performance of extracts from naturally durable heartwood species and their potential as wood preservatives

To avoid the use of toxic synthetic chemicals due to their potential environmental impacts, the feasibility of using heartwood extracts of Tectona grandis and Cedrus deodara as wood preservatives against the subterranean termite, Reticulitermes flavipes and two basidiomycete decay fungi, Trametes versicolor and Rhodonia placenta, was investigated in laboratory experiments. There were no significant differences in feeding for R. flavipes fed solvent-extracted and non-extracted T. grandis in choice and no-choice tests with 100% mortality. Reticulitermes flavipes ignored non-extracted C. deodara (mass loss 1.93%) in choice tests and consumed significantly more solvent extracted C. deodara (mass loss 33.4%) with 64.9% mortality. Complete termite mortality (100%) was observed after exposure to non-extracted C. deodara versus 53% mortality when fed on extracted C. deodara in a no-choice test. When extracted and non-extracted blocks of each wood species were exposed to decay fungi, durability of both heartwood species was reduced post extraction. Extracts removed from wood shavings via Soxhlet extraction were used to treat non-durable southern pine and cottonwood. Both extracts imparted termite resistance to the non-durable species. Weight losses of both non-durable species were reduced at the highest extract concentration tested (10 mg ml−1), and were inversely related to extract concentrations and retentions. Significantly higher termite mortality was observed at the maximum extract concentration tested for either extract. Water leaching of non-durable wood species treated with T. grandis extract did not reduce termite resistance, and no significant difference between mortality of termites on leached versus non-leached samples was observed. Conversely, the weight loss of wood treated with C. deodara extract was significantly greater post leaching. T. grandis and C. deodara extracts showed no protective effects at tested concentrations against decay fungi when applied to non-durable southern pine or cottonwood.

Impact of pollution on the feeding, bioturbation and biomass of Uca annulipes in Gazi and Mikindani mangroves, Kenya

Owuor MA, Aloo-Obudho P, Cannicci S, Gitundu JK. 2017. Impact of pollution on the feeding, bioturbation and biomass of Uca annulipes in Gazi and Mikindani mangroves, Kenya. Ocean Life 1: 61-68. Marine pollution is one of the main anthropogenic factors globally recognized that affect the estuarine and coastal ecosystems. Mangroves received the pollutant since they are intercepting between land and ocean. Despite the utilization of natural mangrove as pollution buffers, how these pollutants might impact the biodiversity of the ecosystems remains a great question. Here, we aimed at determining the impact of pollution on the feeding, bioturbation, and biomass of the fiddler crab Uca annulipes in two regions, Gazi and Mikindani, all along the Kenya Coast. The mangroves in Mikindani on Tudor creek represented peri-urban mangroves that are heavily impacted by municipal wastewater. Meanwhile, the mangroves in Gazi Bay in the South Coast of Kenya served mangroves not affected by direct sewage input. Furthermore, Crabs U. annulipes are one of the most important groups of mangrove epifauna. We adopted a stratified nested design to investigate the impacts of pollution on the feeding, bioturbation, and biomass of U. annulipes. We applied a layered random sampling approach at each site that spanned in 2 × 2 m2 quadrats in desert and Avicennia zones during July, August and October 2005. The data collection depended on each full moon springs and new moon springs. Different parameters were measured, chlorophyll a (Chl a) concentrations in the feeding pellets and unprocessed soils, amount of bioturbated clays (expressed as dry weight of excavated material and feeding pellets), and biomass (dry weight) of U. annulipes. Four-factor Analysis of Variance (ANOVA) tests were applied to determine whether there was a significant difference in feeding, bioturbation, and biomass of U. annulipes within the two sites. Our findings show substantial differences in chlorophyll a concentration in the feeding pellets in the Avicennia zone of the peri-urban mangroves. Moreover chlorophyll a level did not vary between the processed and unprocessed soils in the Avicennia zone. In Gazi, a significant difference in the bioturbated material was recorded compared to Mikindani. The results demonstrate a consistent increase in crab biomass at the peri-urban site, then the non-urban mangroves. The Avicennia zone of the suburban location had a higher U. annulipes biomass compared to the non-urban Gazi. There was no association between the mass of bioturbated material and Uca biomass. The results also show that the amount of excavated material did not relate to the Uca biomass.

All you can eat: the functional response of the cold-water coral Desmophyllum dianthus feeding on krill and copepods.

The feeding behavior of the cosmopolitan cold-water coral (CWC) Desmophyllum dianthus (Cnidaria: Scleractinia) is still poorly known. Its usual deep distribution restricts direct observations, and manipulative experiments are so far limited to prey that do not occur in CWC natural habitat. During a series of replicated incubations, we assessed the functional response of this coral feeding on a medium-sized copepod (Calanoides patagoniensis) and a large euphausiid (Euphausia vallentini). Corals showed a Type I functional response, where feeding rate increased linearly with prey abundance, as predicted for a tentaculate passive suspension feeder. No significant differences in feeding were found between prey items, and corals were able to attain a maximum feeding rate of 10.99 mg C h−1, which represents an ingestion of the 11.4% of the coral carbon biomass per hour. These findings suggest that D. dianthus is a generalist zooplankton predator capable of exploiting dense aggregations of zooplankton over a wide prey size-range.

Poultry Production in Nepal: Characteristics, Productivity and Constraints

Poultry farming is integral part of agriculture in Nepal. The objective of this research was to analyze the prevailing production constraints, characterization of poultry farming and its economic analysis using questionnaire-based survey and on-site investigation. 180 farms were selected from 3 major districts. Garrett’s ranking technique was used to analyze the constraints. Highly significant difference (P<0.01) in size of poultry farm was found. We found significant difference in feeding, housing and drinking system for the chicken. Un-organized chicken marketing channel was observed in the study area. High chicks’ mortality, wastage of feed, insecure vaccination and frequent drop in egg production were characteristic of laying hens. Newcastle disease and Chronic Respiratory Disease were acknowledged as the biggest constraint of chicken production. Government and concerned agencies need to take active part for the extension service to strengthen the health of chicken and organized marketing channel is essential for selling of poultry products which can improve the profit to the farmers.Int. J. Appl. Sci. Biotechnol. Vol 5(2): 222-226

Effects of supplementing an active dry yeast product on rumen microbial community composition and on subsequent rumen fermentation of lactating cows in the mid-to-late lactation period.

The effects of supplementing feed of cows in mid-to-late lactation with an active yeast product (Actisaf Sc 47) were evaluated using 15 Holstein cows in a replicated 3 × 3 Latin square design. The animals were fed a mixed ration with 33% neutral detergent fiber, consisting of timothy hay (29.8%), a commercial concentrate (70.0%) and commercial calcium triphosphate (0.2%), twice daily to meet 105% of their energy requirement. Yeast supplement was set at 0, 5 and 10 g per day over 21-day periods, each of which consisted of 14 days for adaptation followed by 7 days of data collection. Milking performance, plasma metabolite parameters, rumen volatile fatty acids, lipopolysaccharide and microbial properties were measured. Although there were no significant differences in feeding and milking performance or blood parameters associated with supplementation, the acetate to propionate ratio in the rumen fluid tended to decrease (P = 0.08). The population of Bacteroidetes tended to be less prominent (P = 0.07) and the fibrolytic bacterium Fibrobacter significantly increased (P < 0.05) in the rumen fluid of the yeast 10 g group compared with that of the control. These data suggest that effects of supplementing live yeast to cows in mid-to-late lactation may be limited to microbial composition and fermentation characteristics in the rumen.

Diets of Halfbeak Hemiramphus lutkei (Valenciennes, 1847) from Karachi Coast, Pakistan

Objective: To investigate the diets of the Lutke’s halfbeak, Hemiramphus lutkei (H. lutkei) to determine the food and feeding habits. Methods: Samples of H. lutkei were collected from the landing sites of Karachi Coast, Pakistan. Total length was measured to the nearest 0.01 cm using digital slide calipers, and total body weight was measured using an electronic balance with 0.01 g accuracy. The dietary composition was determined from gut content examination and analysis was done using frequency of occurrence and numerical methods. To assess the changes in diet with size, H. lutkei were divided into two size groups, Group 1: 14-20 cm (n=250) and Group 2: 21-25 cm (n=160). Results: The total length and body weight of the sampled specimens ranged from 14 to 25 cm and 10 to 23.5 g, respectively. Out of the studied specimens, 45.12% fish stomachs were found to be empty. Dietary composition revealed daphnia, small fish, isopods, unidentified animal materials, ostracods and unidentified plant materials in the gut contents of Lutke’s halfbeak. Therefore, H. lutkei is omnivore fish feeding on algae, zooplankton, small fishes and different food items of both plant and animal origin. According to the Schoener overlap index (C), there was no significant difference in feeding of the two length groups of H. lutkei (C=0.833). On the other hand, the Shannon-Wiener index showed that the prey diversity of the Lutke's halfbeak in Group 1 was lower (H / =1.545) than that of Group 2 (H / =1.653).

Response of Subterranean Termites (Isoptera: Rhinotermitidae) to Stressed Nestmates

Reticulitermes flavipes (Kollar), R. virginicus Banks, and Coptotermes formosanus Shiraki were stressed by holding them at 25°C or 28°C, respectively, in metal pans for 5 d prior to introduction into 1 side of 3-jar arenas (3 containers connected serially) containing freshly-collected nestmates. After 14 d, mass loss of wooden blocks was determined for blocks from the arena side to which stressed termites were added (treated) as well as those from the opposite side (control). Feeding effects of termite exposure to stress were inconsistent among species. For R. flavipes, there was no significant difference in feeding; whereas loss of block mass on the treated side in R. virginicus arenas was significantly greater (P = 0.0017) than that on the control side of the arenas. For C. formosanus, mass loss of wafers also was significantly greater (P = 0.0284) on the treated side of the arenas, similar to the response of R. virginicus.

Impacts of Soil Moisture Level on Consumption and Movement of Three Sympatric Subterranean Termites (Isoptera: Rhinotermitidae) in a Laboratory Assay

Three subterranean termite species, Reticuliternes flavipes (Kollar), Reticulitermes tibialis Banks, and Reticulitermes virginicus (Banks), were collected from locations in northern Indiana and tested under laboratory conditions to determine whether preferential differences exist among species. Foraging behaviors and location of all three species were studied using a linear, three-dimensional assay with a soil moisture gradient (5, 15, 25, 35, 45, and 55% moisture by weight) and quantified by (1) consumption weights and (2) location counts. In a 7-d period, R. flavipes and R. tibialis consumed almost twice as much filter paper as R. virginicus. No significant difference in feeding was attributed to moisture level for R. tibialis, but there were differences for R. flavipes and R. virginicus. In terms of location of harborage, there were clear patterns associated with moisture level, as predicted using a Poisson distribution. Results from consumption and location data show unique patterns among species, and illustrate species-specific variation in feeding location and nesting preference in response to moisture. There are significant differences in movement patterns, consumption, and mortality among Indiana Reticulitermes according to the laboratory assay. These findings contribute to the overall understanding of midwestern Reticulitermes termites.

Efficacy of multiple biocontrol agents against the sweet potato whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) on tomato

Abstract: Biological control provides an environmentally harmonious and potentially stable management tactic to combat noxious pests such as Bemisia tabaci, notorious for its resistance to synthetic pesticides. Bioassays conducted under control chamber conditions integrating applications of the parasitoid Encarsia formosa, reared for 20 years on Trialeurodes vaporariorum, and the fungus Verticillium lecanii on the third‐fourth instar nymphs of B. tabaci on tomato, showed a comparable effect between the parasitoid‐fungus combined treatment and the fungus treatment alone (70.7% vs. 70.4%). Analysis of our results indicates antagonism between the two biocontrol agents related to the parasitoids’ ability to discriminate between infected and healthy B. tabaci nymphs. The parasitoid treatment alone produced 36.3% mortality, with no mortality in the distilled water controls. The behavioural performance of the parasitoid could have either genetic or environmental causes. Bioassays studying the feeding habit of the imported mirid predator Macrolophus caliginosus (adults) and the indigenous mirid Camptotylus reuteri (nymphs and adults) on eggs, or early second instar nymphs of B. tabaci, and choice preference tests indicated a significant difference in feeding between M. caliginosus and C. reuteri. There was no significant difference in percentage feeding of M. caliginosus on eggs (2.2%) or second instar nymphs (8.0%). There was a significant difference in feeding of M. caliginosus adults (18.6%) when offered eggs and second instars in the same arena compared with eggs or second instars offered separately. These results could be attributed to the biological behaviour of the predator having a type III functional response. Studies with the local C. reuteri species showed no significant difference in adult and nymphal consumption on second instars of B. tabaci compared with nymphs on eggs. However, C. reuteri adults fed less on eggs compared with nymphs. This local predatory species appears to be more efficient than M. caliginosus in feeding on particular stages of B. tabaci without depending on prey density. This is further supported by the low consumption of both adults and nymphs in the choice test (4% and 2.3%, respectively) compared with M. caliginosus adults (18.6%).

Leptin resistance and enhancement of feeding facilitation by melanin-concentrating hormone in mice lacking bombesin receptor subtype-3.

Mice lacking either bombesin receptor subtype (BRS)-3 or gastrin-releasing peptide receptor (GRP-R) exhibit feeding abnormalities. However, it is unclear how these receptors are associated with feeding regulation. In BRS-3-deficient mice, we found hyperphagia, subsequent hyperleptinemia, and brain leptin resistance that occurred after the onset of obesity. To explore the cause of this phenomenon, we examined changes in feeding responses to appetite-related neuropeptides in BRS-3-deficient, GRP-R-deficient, and wild-type littermate mice. Among orexigenic neuropeptides, the hyperphagic response to melanin-concentrating hormone (MCH) was significantly enhanced in BRS-3-deficient mice but not in GRP-R-deficient mice. In addition, the levels of MCH-R and prepro-MCH mRNAs in the hypothalamus of BRS-3-deficient mice were significantly more elevated than those of wild-type littermates. There was no significant difference in feeding between BRS-3-deficient and wild-type littermate mice after treatment with bombesin (BN), although the hypophagic response to low-dose BN was significantly suppressed in the GRP-R-deficient mice. These results suggest that upregulation of MCH-R and MCH triggers hyperphagia in BRS-3-deficient mice. From these results, we assume that the BRS-3 gene deletion upsets the mechanism by which leptin decreases the expression of MCH-R and that this effect may be mediated through neural networks independent of BN-related peptides such as GRP-R.

Exposure of beef cattle to sub-clinical doses of Microcystis aeruginosa: toxin bioaccumulation, physiological effects and human health risk assessment

Yearling beef cattle were fed 1×10 5 cells ml −1 of toxic Microcystis aeruginosa in their drinking water for a period of 28 d. Feed and water intakes of four control and four treated animals remained unchanged following introduction of M. aeruginosa into the drinking water of the treatment animals, and there were no significant differences in feed and water intakes between control and treated animals. We tested the blood plasma of both control and treated animals twice each week for elevated concentrations of the liver enzymes γ-glutamyl transferase (GGT), glyceraldehyde dehydrogenase (GADH), amino aspartate transferase (AST) and bilirubin. All tests were negative indicating no measurable liver dysfunction resulting from microcystin intoxication. We also tested for the presence of free microcystin in the liver and blood plasma by HPLC and ELISA and for total microcystin (free+bound) in the liver by GC–MS. If all the ingested microcystin was bioaccumulated within the liver, the concentration would have exceeded 3 μg MCYST-LR g −1 fresh weight. HPLC and GC–MS analysis of the liver tissue and blood plasma from treated animals failed to detect any microcystins. ELISA analysis of liver tissue extracts from the treated animals indicated microcystin concentrations as high as 0.92 μg MCYST-LR equivalents g −1 fresh weight although none was indicated in the blood plasma. The microcystin concentrations measured by ELISA in livers of treated animals were more than 1000 times higher than the limit of quantification by HPLC and GC–MS indicating the ELISA results were almost certainly due to cross reactivity with something other than intact MCYST-LR. Based on the detection limits of the HPLC and the per capita daily consumption of beef in Australia, it appears that consumption by beef cattle of water containing M. aeruginosa cell concentrations up to 1×10 5 cells ml −1 for 4 weeks would not produce concentrations of microcystin within the liver or blood plasma that would present an unacceptable risk to human health based on World Health Organization protocols for determining such risks.

PHYSIOLOGICAL AND BEHAVIORAL RESPONSES OF STONEFLY NYMPHS TO ENHANCED LIMESTONE TREATMENT OF ACID MINE DRAINAGE

A new acid mine drainage (AMD) treatment system uses pulsed, fluidized beds of limestone, and carbon dioxide pretreatment of influent AMD, to enhance limestone neutralization of AMD. We conducted laboratory studies to evaluate the behavior and physiology of larval stoneflies ( Pteronarcys proteus, Plecoptera) exposed to effluents produced by the treatment system. Survival, sodium balance, drift, and feeding responses by P. proteus to treated and untreated AMD were examined. P. proteus nymphs exhibited significant losses of whole body sodium in exposures to untreated AMD. Nymphs exposed to treated effluents experienced no loss of whole-body sodium. Nymphs exposed to untreated AMD showed elevated drift rates and depressed feeding rates relative to those of nymphs exposed to treated AMD, and to AMD-free controls. No significant differences in feeding or drift behavior occurred between nymphs exposed to treated effluents and those exposed to AMD-free controls. The treatment system, with and without CO 2 pretreatment, provided water that was not toxic to the test animals, and that allowed normal behavioral and physiological function.

Genetic transformation of potato with nptII-gus marker genes enhances foliage consumption by Colorado potato beetle larvae

Little is known about the effect of transgenic plants containing commonly used marker genes, such as aph(3′)II (nptII encoding neomycinphosphotransferase) and uidA (gus encoding β-glucuronidase) on insect feeding behaviour. We report here, for the first time, that transgenic potato plants containing only nptII and gus marker genes enhance foliage consumption by the Colorado potato beetle (CPB, Leptinotarsa decemlineata S.). Transformation of potato cultivar Desiree was performed with Agrobacterium tumefaciens. Internode explants were inoculated with different strains of bacteria, carrying either nptII-gus or nptII alone. A total of 180 transgenic and untransformed control plants were grown in the greenhouse for the analysis of food consumption by CPB. For each transformed and untransformed line tested, four bioassays were conducted each consisting of 10 second-instar larvae feeding independently on a 2 cm diameter leaf disc for 20 h. Our data show up to 50% increase of mean foliage consumption on plants transformed with the nptII-gus construct, indicating that transgenic plants containing these marker genes can affect the feeding behaviour of the insects. These results were obtained from the ‘primary regenerants’ (R0 lines) as well as from tuber-derived plants (R1 lines). Further tests with transgenic plants containing the nptII marker gene only, showed no significant difference in feeding when compared to untransformed control plants, allowing us to rule out a direct effect of this marker gene on foliage consumption by the insect larvae. It is suggested that gus protein is involved in the increase of foliage consumption by CPB.

Swim bladder inflation in larvae of cultured sand whiting, Sillago ciliata Cuvier (Sillaginidae)

Failure of the swim bladder to inflate can cause mortality in intensively cultured marine fish larvae. Surface access and light intensity are two key factors which influence inflation. Sand whiting ( Sillago ciliata) have a diel pattern of nocturnal swim bladder inflation in the wild. The objectives of this study were to determine when initial swim bladder inflation starts in cultured S. ciliata larvae, if surface access is required, and the effects of light. S. ciliata was found to inflate the swim bladder at night and completely deflate it during the day. This pattern starts on day 4, when the mean larval length is 2.8 mm and coincides with the completion of yolk sac and oil globule absorption, the start of exogenous feeding, and heavy larval mortality. Maximum swim bladder volume in 5-day-old larvae peaks 2 h after dusk and then gradually declines before dawn. The diel pattern of nocturnal inflation continues until day 17 when increasing numbers of larvae (mean length 6.4 mm) retain partially inflated swim bladders during the day. Experiments with 12-, 15- and 19-day-old larvae, siphoned into 2-litre beakers at midday, show that larvae respond to darkness by inflating their swim bladders. Placing oil on the surface of darkened beakers did not prevent swim bladder inflation in larvae from day 12. Swim bladder volumes were small and not significantly different for larvae in beakers with low light (413 lx) and high light (1360 lx). However, significant differences in feeding were observed with larvae, under high light, eating more rotifers than larvae in low light. Larvae did not feed in the dark. It is proposed that nocturnal swim bladder inflation allows S. ciliata larvae to conserve energy at night when they are not feeding. Although S.ciliata larvae have a different swim bladder inflation pattern from that of most species, it is suggested that it will present few additional culture problems. A light intensity of 1000–1500 lx, and a constant photoperiod are recommended to maximise swim bladder inflation.

Variations in Ground White Pine Bark Concentration in Artificial Diet in Relation to Egg Laying, Feeding, and Mortality of Pissodes strobi (Coleoptera: Curculionidae)

Variations in concentrations of ground white pine bark incorporated into artificial diet were studied to determine their effect on egg laying and feeding behavior of white pine weevils, Pissodes strobe (Peck). Significant differences in feeding and egg laying responses were detected between adults fed diets containing 5 and 10% ground bark. White pine weevil larvae reared on the diet containing 1% ground bark had a higher mortality level than those reared on the diet containing 5% ground bark. Weevil females fed the diet containing 5% ground bark were significantly heavier than those reared on the diet with 1% ground bark. Insect development times did not differ significantly between the two concentrations of ground bark. Adults exposed to a natural substrate were stimulated to oviposit, and viable eggs were laid.

Beak Trimming Effects on Beak Length and Feed Usage for Growth and Egg Production ,

Two experiments were conducted to compare beak treatment effects on pullets of three genetic stocks. Within each stock, equal numbers were assigned to three treatments: no beak trimming (IN), beak trimming once (1X), and beak trimming twice (2X). Beak treatment, genetic stock, and age effects along with interactions among main effects were examined for production-associated traits during rearing and brief periods of early egg production.Beaks of 1X and 2X pullets remained shorter than those of IN pullets through final measurements at 36 and 32 wk of age in Experiments 1 and 2, respectively. However, differences in beak length decreased as age increased. Upper beaks of 2X pullets remained shorter than those of 1X pullets, but lower beaks of 1X and 2X pullets did not differ by 20 wk in Experiment 2.Weight gains, feed usage, and efficiency of growth were affected by beak treatments. Beak trimming reduced gains, feed eaten, feed wasted, and total feed used, and 2X pullets used their feed more efficiently for weight gain and egg production. A general decrease occurred in differences among beak treatments for weight gains, feed eaten, feed wasted, and efficiency of gains with increasing age during rearing. Nevertheless, significant differences in feed consumed, feed wasted, and efficiency of feed used for egg production indicated an economic advantage in favor of beak trimming.