Higher Egg Production Research Articles

Effects of single and combined genotypes of MC4R and POU1F1 genes on two production traits in Langshan chicken

The objective of this study was to analyze the effects of single and combined genotypes of MC4R and POU1F1 genes in Chinese well-known indigenous chicken (Langshan chicken) population. Genetic variants within MC4R gene and POU1F1 gene were screened through PCR-SSCP and DNA sequencing methods. A C/T mutation at nt 944 in MC4R gene (NC_006089.2:g. 944C>T) and a G/A mutation at nt 3109 in POU1F1 gene (NC_006088.2:g. 3109 G>A) were identified. Associations between the mutations of the two genes with two production traits were analyzed. The results showed that, at MC4R locus, individuals with BB and AB genotypes had highly significantly higher body weight at 16 weeks (p < 0.01) than did those with the AA genotype. And, individuals within AA and AB genotypes had significantly higher egg numbers at 300 days (p < 0.05). At POU1F1 locus, individuals with CD genotype had higher body weight at 16 weeks and egg numbers at 300 days (p < 0.05). Furthermore, combined genotypes from these two loci were found to be associated with egg numbers at 300 days (p < 0.05). The individuals within combined genotype AB/CD had higher egg production. Therefore, variations identified within the MC4R and POU1F1genes are suitable for future use in identifying chickens with the genetic potential of higher body weight and reproductive traits, at least in the population of Langshan chickens.

Social familiarity relaxes the constraints of limited attention and enhances reproduction of group‐living predatory mites

In many group-living animals, within-group associations are determined by familiarity, i.e. familiar individuals, independent of genetic relatedness, preferentially associate with each other. The ultimate causes of this behaviour are poorly understood and rigorous documentation of its adaptive significance is scarce. Limited attention theory states that focusing on a given task has interrelated cognitive, behavioural and physiological costs with respect to the attention paid to other tasks. In multiple signal environments attention has thus to be shared among signals. Assuming that familiar neighbours require less attention than unfamiliar ones, associating with familiar individuals should increase the efficiency in other tasks and ultimately increase fitness. We tested this prediction in adult females of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. We evaluated the influence of social familiarity on within-group association behaviour, activity, predation and reproduction. In mixed groups (familiar and unfamiliar), familiar predator females preferentially associated with each other. In pure groups (either familiar or unfamiliar), familiar predator females produced more eggs than unfamiliar females at similar predation rates. Higher egg production was correlated with lower activity levels, indicating decreased restlessness. In light of limited attention theory, we argue that the ability to discriminate between familiar and unfamiliar individuals and preferential association with familiar individuals confers a selective advantage because familiar social environments are cognitively and physiologically less taxing than unfamiliar social environments.

Effects of metabolizable energy and balanced protein on egg production, quality, and components of Lohmann Brown laying hens

SUMMARY A 4 × 3 factorial experiment with 4 dietary ME levels (2,400, 2,550, 2,700, and 2,850 kcal/ kg) and 3 CP levels (14.5, 16.0, and 17.5%) was conducted to determine the effects of ME and CP on egg production (EP) performance, egg quality, and egg components of laying hens. The protein ingredients were composed of soybean meal (36.5%), cottonseed meal (36.5%), and canola meal (27.0%). A total of 900 commercial Lohmann Brown pullets, 26 wk of age, were randomly assigned into 12 treatments (5 replicates with 15 birds per replicate). Feed and water were provided ad libitum throughout the experiment (12 wk). The optimum intake of ME and CP for maximum egg production, egg mass (EM), and feed conversion ratio (FCR) was calculated. There was an interaction between ME and CP on EP, EM, and FCR (P < 0.001). By response surface analysis, the ranges of estimated optimum ME and CP intake were 325.7 to 331.7 kcal/d (2,591 to 2,683 kcal/kg) and 19.5 to 20.7 g/d (15.58 to 16.64%), respectively, for optimum EP, EM, and FCR. The highest EP and EM were observed with 16% CP (21.13 g/d) and 2,400 kcal/kg of ME (316.95 kcal/d) in the diet. Diets with high CP (17.5%) and low energy (2,400 kcal/kg) exhibited the poorest EP (71.58%), EM (42.15 g/d), egg shell quality (0.289 mm), and broken egg ratio (0.25%). Thus, moderate ME and high balanced protein are very important for optimizing the FCR, EP, and EM of Lohmann Brown laying hens.

Effect of Monochromatic and Combined Light Colour on Performance, Blood Parameters, Ovarian Morphology and Reproductive Hormones in Laying Hens

We evaluated the effect of monochromatic and combined light emitting diode (LED) light colour on performance, ovarian morphology, and reproductive hormone and biochemical blood parameters in laying hens. A total of 600 Hy-line Brown pullets, 12 weeks of age, were divided (25×4×6 = birds × replications × treatments) as follows: red (R), green (G), blue (B), and combinations of R → G and R → G → B treatments. Fluorescent white light (W) was the control. The results showed that higher egg production was found under the monochromatic R and combination R → G treatments, and that heavier eggs were laid by the B and G treatments (P<0.05). Consequently, better feed conversion ratio was attained in the R → G treatment. Serum follicle stimulating hormone and 17 -estradiol levels were significantly higher in the R and R → G treatments. B treated birds came into production 15 days later than those treated with R light. Organ weight (ovary and stroma) and ovarian follicle numbers (1-3 and 4-6 mm) were significantly higher in R treated birds, as well as serum glucose and triglyceride contents. Serum IgG concentrations and the heterophil to lymphocyte ratio were not influenced by light colour. In these laying hens, 14 h R with 2 h G light in the later part of the day increased reproductive hormone levels, ovarian weight, and follicle number and hence increased egg production. Thus, these results suggest that a combination of R → G light may be comparable with monochromatic R light to enhance egg production in laying hens.

Production Performance, Egg Quality and Biochemical Parameters of Three Way Crossbred Chickens with Reciprocal F1 Crossbred Chickens in Sub-Tropical Environment

A total of 225 hens (18 weeks of age) of each Rhode Island Red male x Fayoumi female (RIFI), Fayoumi male x Rhode Island Red female (FIRI) and White Leghorn male x FIRI female (RLH) were maintained on deep litter system for a period of 72 weeks of age. In floor pens, each crossbred chicken was randomly distributed between pens, with 21 to 24 birds of the same breed per pen (2.00 to 2.50 ft2/bird). The results revealed that the age of sexual maturity was lowest in RIFI followed by FIRI and RLH chickens. The highest egg production was obtained by three-way crossbred chickens (RLH) as compared with two-way crossbred chickens (RIFI and FIRI). The highest egg weight was observed in RLH than those of FIRI and RIFI crossbred chickens. The internal egg quality parameters included yolk weight, albumen weight, yolk + albumen weight and albumen height were same in all crossbred chickens. There was non-significant (P>0.05) difference in blood glucose, triglyceride, cholesterol, calcium, protein, uric acid and ALP values among all crossbred chickens. It may be concluded that three-way crossbred chickens (RLH) showed better egg traits than two-way crossbred chickens (RIFI and FIRI) with lower mortality. The RIFI crossbred chickens achieved sexual maturity earlier than both FIRI and RLH crossbred chickens with lower egg traits.

Investigation on the Effects of Various Protein Levels with Constant Ratio of Digestible Sulfur Amino Acids and Threonine to Lysine on Performance, Egg Quality and Protein Retention in Two Strains of Laying Hens

An experiment was conducted to determine the possibility of using various levels of crude protein (CP) by providing laying hens with constant levels of digestible sulfur amino acid, threonine and lysine to improve performance and egg quality. The experiment was conducted as a completely randomized block design in a factorial arrangement (4×2) with 8 replicates of 10 hens in each. Factors included 4 levels of CP (18.5%, 17.5%, 16.5% and 15.5%) and 2 strains (LSL and Hy-Line W-36) of laying hens. Hens were fed experimental diets from 25 to 33 weeks of age. Production performance was measured for eight weeks and egg quality characteristics were determined at 29 and 33 weeks of age. Protein reduction decreased egg weight, egg mass and hen body weight linearly (P≤0.01). Egg production was not affected by protein reduction but feed efficiency, and average daily feed intake increased significantly (P≤0.01). Lohmann Selected Leghorn laying hens showed significantly higher egg production, egg weight, egg mass, weight gain, feed efficiency and feed intake compared to the W-36 laying hens (P≤0.01). Shell thickness increased linearly as protein levels decreased (P≤0.05). There were significant differences between two strains on the egg quality characteristics (P≤0.01). Significant (P≤0.05) CP × strain interactions were observed for hen weight, albumen height, Haugh units, yolk and shell percentage. Based on the results of this experiment, a reduction in dietary protein level (from 18.5% to 15.5%), without any alteration in digestible TSAA and Thr: Lys ratio, led to inferior egg mass and feed conversion ratio during the peak production period.

Insulin-like growth factor-1 polymorphism and its association with economic traits in Kadaknath and its crossbred birds

Insulin-like growth factor-1 (IGF-1) gene polymorphism has been investigated by PCR-RFLP method on 80 unrelated female birds each of Kadaknath and its crossbred selected randomly from Department of Poultry Science of the University. The 3 different RFLP patterns revealed restriction fragment of 621, 364 and 257 bp sizes in Kadaknath and Kadaknath crossbred birds. This indicated presence of 2 restriction sites at 621 bp (site A) and 364, 257 bp (site B) position in 621bp amplicon. Genotypic frequencies in Kadaknath and Kadaknath crossbred birds were found to be 0.41 and 0.35 for AA genotype, 0.37 and 0.38 for AB genotype and 0.21 and 0.27 for BB genotype, respectively, whereas the allelic frequencies in Kadaknath and Kadaknath crossbred birds were 0.60 and 0.54 for A allele and 0.40 and 0.46 for B allele respectively. The Kadaknath population was in Hardy Weinberg equilibrium, however Kadaknath crossbred population under study was not in Hardy Weinberg equilibrium. The differences between least squares means of various genotypes for age at sexual maturity and adult body weight at 20, 40 and 52 weeks were nonsignificant (P&gt;0.05). Genotype BB was superior for body weight at 20, 40 and 52 weeks in Kadaknath and Kadaknath crossbred birds. Significant breed × genotype interaction was found for egg production at 40 weeks of age and higher egg production was recorded for AA genotype in Kadaknath and AB genotype in Kadaknath crossbred birds. Genotype AA was superior for egg weight at 40 and 52 weeks in Kadaknath and Kadaknath crossbred birds.

Comparative study of growth performance, egg production, egg characteristics and haemato-biochemical parameters of Desi, Fayoumi and Rhode Island Red chicken

A total of 2001 un-sexed day-old chicks of each Desi, Fayoumi and Rhode Island Red (RIR) breeds were obtained from hatchery of Poultry Research Institute, Rawalpindi. The birds were maintained on deep litter system for a period of 72 weeks. In floor pens, each breed was reared separately in a single pen until seven weeks of age when 2001 birds were randomly distributed between pens, with 21 to 24 birds of the same breed per pen (2.00 to 2.50 ft2/bird). The results revealed that the average day-old weight was highest in RIR, intermediate in Desi and lowest in Fayoumi. The RIR breed consumed more feed and gained maximum (p<0.05) weight than those of Desi and Fayoumi breeds at all ages of growing phase. The feed conversion was poor (p<0.05) in Desi and better in RIR breed. Desi and Fayoumi chicks had lowest (p<0.05) mortality than RIR breed. The breast and thigh meat composition was found non-significant (p>0.05) amongst three breeds. The age of sexual maturity was lowest in Fayoumi followed by RIR and Desi. The highest egg production was obtained by RIR with 41% followed by Fayoumi (36%) and the Desi breed (29%). The egg weight and egg mass were highest (p<0.05) in RIR, but non-significant (p>0.05) differences were found between Fayoumi and Desi breeds. The internal egg quality parameters including yolk weight, albumen weight, yolk plus albumin weight and albumin height were significantly higher in RIR breed than those of Fayoumi and Desi breeds. However, shell and yolk thickness did not differ significantly amongst three breeds. There was non-significant (p>0.05) difference in blood glucose, triglyceride, cholesterol, calcium, protein, uric acid and alkaline phosphatase values amongst three breeds. There was non-significant (p>0.05) difference in haematological values among all breeds. The total erythrocyte count, haemoglobin and packed cell volume increased with the advancement of age. However, erythrocyte sedimentation rate, mean corpuscular volume and mean corpuscular haemoglobin values decreased gradually with the advancement of age. It may be concluded that overall RIR chickens performed better than Fayoumi and Desi chickens. However, early age of sexual maturity was noticed in Fayoumi chickens, and low mortality was observed in Desi chickens.

Biological aspects and life table parameters of the predacious mite, Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) consuming food types during immature stages and after adult emergence

To investigate the effect of food types on biological aspects and life table parameters of the predacious mite, Neoseiulus californicus (McGregor), immature stages were fed on pollen of maize, Zea mays L. and eggs of Tetranychus urticae Koch, while adult females were offered the same foods and the alternate shift of each food. All individuals of predator females reached adulthood when reared on maize pollen and prey eggs, but their life cycle was significantly longer on pollen than on prey. The shortest preoviposition period of N. californicus occurred after continuous feeding on T. urticae eggs, whereas the longest happened when fed on prey eggs switched to maize pollen. Continuous consuming of maize pollen showed the longest ovipositoin period for the predator, while rearing on maize pollen shifted to prey eggs exhibited the shortest duration. The longest longevity and highest sex ratio of females to total in N. californicus were recorded when continuously utilised pollen, whereas the shortest longevity and lowest sex ratio were noted when continuously consumed prey. On the contrary, the egg production and life table values of the predator were the highest by continuous feeding on prey eggs, while they were the lowest by continuous rearing on maize pollen. Therefore, feeding juveniles on prey eggs and adult females on maize pollen is better for long-term preservation of N. californicus females than continuous feeding on maize pollen due to a shorter developmental duration, a higher egg production and more favourable life table values.

Evaluating the egg production of broiler breeder hens in response to dietary nutrient intake from 31 to 60 weeks of age through neural network models

Faridi, A., Golian, A. and France, J. 2012. Evaluating the egg production of broiler breeder hens in response to dietary nutrient intake from 31 to 60 weeks of age through neural network models. Can. J. Anim. Sci. 92: 473–481. The aim of this study was to evaluate the response of broiler breeder hens in terms of egg production to dietary nutrient intake. Using neural network (NN) models and breaking down the collected data from 98 commercial broiler breeder houses into 3-wk intervals, 10 NN-based models were developed from 31 to 60 wk of age. The data lines were divided into two random subsets of training (n=64) and testing (n=34) sets. The variables of interest for developing the models were metabolizable energy (ME; kcal bird−1 d−1), and crude protein (CP), total sulphur amino acids (TSAA), lysine (Lys), calcium (Ca) and available phosphorus (AP), all in g bird−1 d−1. The random optimization algorithm was applied to the constructed models to find the optimal level of the input variables which maximized egg production during the different intervals. The high R 2 values in all the developed models for both the training and testing sets indicate the accuracy of NN-based models in estimating egg production. The optimization results revealed that breeder hens consuming 485, 473, 471, 466, 460, 452, 448, 442, 437 and 445 kcal of ME bird−1 d−1 showed the highest egg production during the 10 consecutive 3-wk intervals from 31 to 60 wk of age, respectively. Moreover, the optimal performance of hens required the following average intakes from 31 to 60 wk of age (g bird−1 d−1): CP: 23.7; TSAA: 1.05; Lys: 1.07; Ca: 4.91; and AP: 0.58. The results show that energy (kcal bird−1 d−1) and other nutrient requirements (g bird−1 d−1) of broiler breeder hens from 31 to 60 wk of age do not change in consort together with age; therefore using different diets with different dietary nutrient levels during the production cycle may help the nutritionists better meet the requirements of broiler breeder hens. Based on the present study, it appears that company guideline recommendations may underestimate the nutrient requirements of hens during these weeks when egg production is declining gradually.

Differential Gene Expression from Genome-Wide Microarray Analyses Distinguishes Lohmann Selected Leghorn and Lohmann Brown Layers

The Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB) layer lines have been selected for high egg production since more than 50 years and belong to the worldwide leading commercial layer lines. The objectives of the present study were to characterize the molecular processes that are different among these two layer lines using whole genome RNA expression profiles. The hens were kept in the newly developed small group housing system Eurovent German with two different group sizes. Differential expression was observed for 6,276 microarray probes (FDR adjusted P-value <0.05) among the two layer lines LSL and LB. A 2-fold or greater change in gene expression was identified on 151 probe sets. In LSL, 72 of the 151 probe sets were up- and 79 of them were down-regulated. Gene ontology (GO) enrichment analysis accounting for biological processes evinced 18 GO-terms for the 72 probe sets with higher expression in LSL, especially those taking part in immune system processes and membrane organization. A total of 32 enriched GO-terms were determined among the 79 down-regulated probe sets of LSL. Particularly, these terms included phosphorus metabolic processes and signaling pathways. In conclusion, the phenotypic differences among the two layer lines LSL and LB are clearly reflected in their gene expression profiles of the cerebrum. These novel findings provide clues for genes involved in economically important line characteristics of commercial laying hens.

Experimental Evidence for Nutrition Regulated Stress Resistance in Drosophila ananassae

BackgroundThe amount and quality of nutrients consumed by organisms have a strong impact on stress resistance, life-history traits and reproduction. The balance between energy acquisition and expenditure is crucial to the survival and reproductive success of animals. The ability of organisms to adjust their development, physiology or behavior in response to environmental conditions, called phenotypic plasticity, is a defining property of life. One of the most familiar and important examples of phenotypic plasticity is the response of stress tolerance and reproduction to changes in developmental nutrition. Larval nutrition may affect a range of different life-history traits as well as responses to environmental stress in adult.Principal FindingsHere we investigate the effect of larval nutrition on desiccation, starvation, chill-coma recovery, heat resistance as well as egg to adult viability, egg production and ovariole number in Drosophila ananassae. We raised larvae on either protein rich diet or carbohydrate rich diet. We found that flies consuming protein rich diet have higher desiccation and heat shock resistance whereas flies developed on carbohydrate rich diet have higher starvation and cold resistance. Egg production was higher in females developed on protein rich diet and we also found trade-off between egg production and Egg to adult viability of the flies. Viability was higher in carbohydrate rich diet. However, sex specific viability was found in different nutritional regimes. Higher Egg production might be due to higher ovariole number in females of protein rich diet.ConclusionThus, Drosophila ananassae adapts different stress tolerance and life-history strategies according to the quality of the available diet, which are correlated with phenotypic adjustment at anatomical and physiological levels.

Evidence That Marine Reserves Enhance Resilience to Climatic Impacts

Establishment of marine protected areas, including fully protected marine reserves, is one of the few management tools available for local communities to combat the deleterious effect of large scale environmental impacts, including global climate change, on ocean ecosystems. Despite the common hope that reserves play this role, empirical evidence of the effectiveness of local protection against global problems is lacking. Here we show that marine reserves increase the resilience of marine populations to a mass mortality event possibly caused by climate-driven hypoxia. Despite high and widespread adult mortality of benthic invertebrates in Baja California, Mexico, that affected populations both within and outside marine reserves, juvenile replenishment of the species that supports local economies, the pink abalone Haliotis corrugata, remained stable within reserves because of large body size and high egg production of the protected adults. Thus, local protection provided resilience through greater resistance and faster recovery of protected populations. Moreover, this benefit extended to adjacent unprotected areas through larval spillover across the edges of the reserves. While climate change mitigation is being debated, coastal communities have few tools to slow down negative impacts of global environmental shifts. These results show that marine protected areas can provide such protection.

The effect of stocking density on the reproductive output of hatchery-reared Florida apple snails, Pomacea paludosa

The effect of stocking density on the reproductive output of Florida apple snails was investigated with the goal of developing a captive breeding program that would sustain year-round production and yield a high number of juvenile snails. We examined stocking densities of 50, 100, and 150 snails/m2 to determine the threshold at which density negatively affects reproduction. Adult snails were added to tanks in a recirculating aquaculture system at a 1:1 sex ratio and reproductive output was followed for 8weeks. The total number of clutches per tank and the number of eggs per clutch were recorded daily. The number of egg clutches produced in each tank was standardized per female to assess among treatment differences. Once hatched, the juveniles were counted and the percent hatch rates were determined for each clutch. The findings of the study demonstrated that density affected the mean number of clutches laid per female per week with snails in the 50 snails/m2 treatment having higher egg production than snails stocked at 100 and 150 snails/m2 treatments. Similarly, the number of juveniles produced per female was also higher in the lowest density treatment. There were no significant differences between treatments for egg characteristics (number of eggs per clutch and percent hatch rate). Based on these results, it is recommended that adult snails be stocked at 50 snails/m2 to yield optimum egg production per female, attain the highest number of juveniles, and to sustain production for a reliable captive breeding program.

Genetic variations alter physiological responses following heat stress in 2 strains of laying hens

Heat stress (HS) is a major problem experienced by the poultry industry during high-temperature conditions. The ability to manage the detrimental effects of HS can be attributed to multiple factors, including genetic background of flocks. The objective of the present study was to determine the genetic variation in HS effects on laying hens' physiological homeostasis. Ninety 28-wk-old White Leghorn hens of 2 strains were used: a commercial line of individually selected hens for high egg production, DeKalb XL (DXL), and a line of group-selected hens for high productivity and survivability, named kind gentle bird (KGB). Hens were randomly paired by strain and assigned to hot or control treatment for 14 d. Physical and physiological parameters were analyzed at d 8 and 14 posttreatment. Compared with controls, HS increased hen's core body temperature (P < 0.05) and decreased BW (P < 0.05) at d 8 and 14. Heat shock protein 70 concentrations in the liver were greater in hens exposed to HS (P < 0.05). Compared with DXL hens, KGB hens had higher heat shock protein 70 concentrations (P < 0.05). The hens' liver weight decreased following HS, with less of a response in the KGB line (P < 0.05). The data indicate HS has detrimental effects on the physiology of laying hens due to genetic variations. These data provide evidence that is valuable for determining genetic interventions for laying hens under HS.

The effects of using different levels of lemon balm (Melissa officinalis L.) medicinal plant on performance, egg traits, blood biochemical parameters and Immunity cells of laying hens

This experiment was conducted to evaluate the effects of different levels of Lemon balm (Melissa officinalis L.) medicinal plant dried aerial part powder on performance, egg traits, blood biochemical and Immunity cells of laying hens. 180 laying hens (W36 strain) from 46 until 58 weeks of age were used in a completely randomized design in five treatments (0, 0.5, 1, 1.5 and 2%) and three replicates (12 birds per replicate). Using different levels of lemon balm significantly affected the performance, egg traits and blood biochemical parameters of laying hens (p < 0.05). The lowest feed conversion ratio (3.1), the highest egg production (56.85%) and egg mass (35.51 g/hen/day) were observed in Treatment 2 (0.5% lemon balm); the best yolk index (5.17) was obtained in Treatment 4 by using 1.5% of lemon balm medicinal plant whereas the highest Haugh unit (87.91) obtained in control group. The lowest (188.22 mg/dl) and the highest (280.22 mg/dl) amounts of blood glucose were observed in Groups 1 and 2. The results showed that there are no significant differences between treatments on blood immunity cells levels, but numerically the highest percentage of lymphocytes (86.67%) and the lowest percentage of hetrophiles (11%) and the lowest ratio of H/L (0.132) were observed in Treatment 2 by using 0.5% of lemon balm. The overall results showed that the use of 0.5% of lemon balm medicinal plant in the diets of laying hens have positive effects on their performance, egg traits, blood biochemical parameters and Immunity cells.

Egg Production and Calcium-Phosphorus Utilization of Laying Hens Fed Diets Supplemented with Phytase Alone or in Combination with Organic Acid

An experiment was conducted to determine the effects of dietary organic acid and phytase supplementation on performance and calcium and phosphorus utilization in laying hens. Two hundred 23- wk-old Brown Nick layers were randomly allocated into 50 cages (42 x 50 cm) each containing 4 birds. Each dietary treatment had 5 replications and each replication comprised two adjacent cages. Corn-soybean meal based rations were used. Five dietary treatments were formed as followed: (1) a basal ration with no supplemental P (negative control, NC) (2750 kcal ME/kg, 17% CP, 0.34% total P, 3.8% Ca), (2) basal ration supplemented with dicalcium phosphate (1.4%) (positive control, PC), (3) basal ration supplemented with 0.035% phytase (ZY Phytase II-5, NC+P), (4) basal ration supplemented with 1.0% organic acid (Salstop SD, NC+OA) and (5) basal ration supplemented with both 0.035% phytase and 1.0% organic acid (NC+POA). Water and feed were provided for ad libitum consumption and a lighting program of 16 h light : 8 h dark was applied throughout the study. NC treatment resulted in body weights that were lower (p<0.05) than those of hens fed diets supplemented with phytase, organic acid, or both. Hens fed diets supplemented with dicalcium phosphate, phytase and organic acid and phytase had higher egg production (p<0.001) (91.3, 86.1 and 93.7% respectively) compared to hens fed either basal diet (78.5%) or basal diet with organic acid supplementation (78.6%). Additionally, the unsupplemented or organic acid supplemented diet had lower FI and higher FCR (p<0.01). Hen tibia ash and serum calcium levels were not affected by the dietary treatments whereas diets supplemented with dicalcium phosphate, phytase and phytase + organic acid had higher (p<0.01) serum inorganic phosphorus. The results of this study indicate that dietary phytase improves P utilization in corn-soybean meal based diets with no supplemental P and acidification of gastrointestinal tract may further improve this utilization.

Effects of a future warmer ocean on the coexisting copepods Calanus finmarchicus and C. glacialis in Disko Bay, western Greenland

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 447:87-108 (2012) - DOI: https://doi.org/10.3354/meps09551 Effects of a future warmer ocean on the coexisting copepods Calanus finmarchicus and C. glacialis in Disko Bay, western Greenland Sanne Kjellerup1,2,4, Michael Dünweber1, Rasmus Swalethorp1,4, Torkel Gissel Nielsen1,2,4,*, Eva Friis Møller1, Stiig Markager1, Benni Winding Hansen3 1Department of Bioscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark 2Greenland Climate Research Center, Greenland Institute of Natural Resources, PO Box 570, 3900 Nuuk, Greenland 3Roskilde University, Department of Environmental, Social and Spatial Change, 4000 Roskilde, Denmark 4Present address: National Institute of Aquatic Resources, DTU Aqua, Section for Ocean Ecology and Climate, Technical University of Denmark, Kavalergården 6, 2920 Charlottenlund, Denmark *Corresponding author. Email: tgin@aqua.dtu.dk ABSTRACT: The effects of temperature and food was examined for Calanus finmarchicus and C. glacialis during 3 phases of the phytoplankton spring bloom in Disko Bay, western Greenland. The 2 species were collected during pre-bloom, bloom, and post-bloom and exposed to temperatures from 0 to 10°C, combined with deficient or excess food. Fecal pellet and egg production were measured as indices for grazing and secondary production, respectively. Furthermore, changes in body carbon, nitrogen, and lipid content were measured. C. glacialis sampled before the bloom and incubated with excess food exhibited high specific egg production at temperatures between 0 and 2.5°C. Higher temperatures did not increase egg production considerably, whereas egg production for C. finmarchicus more than tripled between 2.5 and 5°C. Starved C. glacialis produced eggs at all temperatures stimulated by increasing temperatures, whereas starved C. finmarchicus needed temperatures above 5°C to produce eggs fueled by their lipid stores. Few C. finmarchicus had mature gonads at the initiation of the pre-bloom and bloom experiment, and egg production of C. finmarchicus therefore only increased as the ratio of individuals with mature gonads increased. During the bloom, both C. glacialis and C. finmarchicus used the high food availability for egg production, while refueling or exhausting their lipid stores, respectively. Finally, during the post-bloom experiment, production was low by C. finmarchicus, whereas C. glacialis had ­terminated production. Our results suggest that a future warmer ocean will reduce the advantage of early spawning by C. glacialis and that C. finmarchicus will become increasingly prevalent. KEY WORDS: Calanus finmarchicus · Calanus glacialis · Global warming · Egg production · Fecal pellet production · Population dynamics Full text in pdf format Supplementary material PreviousNextCite this article as: Kjellerup S, Dünweber M, Swalethorp R, Nielsen TG, Møller EF, Markager S, Hansen BW (2012) Effects of a future warmer ocean on the coexisting copepods Calanus finmarchicus and C. glacialis in Disko Bay, western Greenland. Mar Ecol Prog Ser 447:87-108. https://doi.org/10.3354/meps09551 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 447. Online publication date: February 13, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.

Melanin-based coloration reflects alternative strategies to cope with food limitation in pigeons

Variation in genetic-based coloration is widespread among vertebrates, yet the underlying mechanisms explaining this polymorphism maintenance remain poorly known. Gene-by-environment interactions on fitness traits in a fluctuating environment are often invoked to explain the maintenance of such color diversity. According to this hypothesis, variation in coloration could signal alternative life-history strategies to cope with variable environmental conditions. However, empirical studies testing this hypothesis are still rare. Here, we aimed at comparing the variation of body mass maintenance behavior and reproductive traits between differently colored individuals in alternative environments. We exposed differently colored captive feral pigeons to different food conditions and immune challenges and measured their investment in body mass maintenance, egg laying, and offspring quality. Under food restriction, darker eumelanic females had a higher egg production, but darker adults tended to lose more body mass than paler conspecifics. Moreover, offspring reared in food-limited conditions had a higher body mass at fledging when sired by darker biological fathers, suggesting a positive genetic effect of a darker eumelanic coloration in harsh food conditions. In contrast, when food was abundant, pale- and dark-colored females had a similar egg production, but darker adults lost significantly less body mass than paler conspecifics. The immune challenge had no effect on adult body mass maintenance and reproduction. Differently colored individuals may thus display alternative reaction norms to different food conditions, suggesting that eumelanin-based coloration reflects how animals cope with variations in food availability. Spatiotemporal heterogeneity of food availability in natural systems may thus play a central role in the evolution of melanin-based coloration in wild animal populations.

Yumurtlayan Japon Bıldırcınlarında Ayçekirdeği Yağı Yerine Tavuk Çevirme Yağı Kullanımının Performans, Kan Parametreleri, Yumurta Sarısının Kolesterol ve Yağ Asidi Kompozisyonuna Etkisi

This study was carried out to determine the effect of using chicken grill oil instead of the sunflower oil in laying Japanese quail diets on egg production, feed intake, feed conversion ratio, egg quality, blood parameters, cholesterol and fatty acid composition of egg yolk. A total of 192, thirteen week old Japanese quail were allocated to four groups with six replicates containing eight quail each. The diets were isonitrogenous and isocaloric and included 20 % crude protein and 2900 kcal/kg ME. The diets contained 5% sunflower oil (SO1), 5% chicken grill oil (CO1), 7.5% sunflower oil (SO2), 7.5% chicken grill oil (CO2). Experimental diets and water were provided ad libitum throughout the 9 weeks. There were no significant differences in initial body weight among groups, but there were highly significant (p<0.001) differences in final body weight among groups: 296.62, 286.62, 308.24, 276.35 g for SO1, CO1, SO2 and CO2 respectively. Higher egg production (p<0.001) was obtained for quail fed the CO1 and the CO2 diet (5% and 7.5% chicken grill oil respectively) than for quail fed the SO1 or the SO2 (5% and 7.5% sunflower oil). The cholesterol content in blood serum (195.61, 197.12, 157.37 and 176.49 mg/dl respectively) was not statistically significant. At the end of the study cholesterol content of the egg yolk (49.70, 49.54, 45.55 and 44.06 mg/g egg yolk respectively) was lowest in (p<0.05) the laying quail fed the CO2 diet. All blood parameters including haemoglobin, heamotocrit, serum cholesterol and serum glucose were not affected by diets except serum triglyceride and serum protein p<0.01). Dietary chicken grill oil had no adverse effect on egg weight, cholesterol and fatty acid composition of the egg yolk and feed conversion ratio. Therefore, chicken grill oil can be use up to 7.5% of the laying quail diets.