Daily Egg Production Research Articles

The effect of temperature and humidity index on egg-laying and hatching parameters in Japanese quail

The objective was to measure the effect of temperature-humidity index (THI) on egg laying and hatching parameters. Quails were randomly transferred to two cage blocks at 20.55 ± 0.05ºC and 52.25 ± 0.68% relative humidity (RH), accepted as 66 THI group. One cage block was transferred to the next room at 16.15 ± 0.13ºC and 70.77 ± 0,38 % RH considered as 61 THI group. In the second stage of the study, the cage block previously accepted as 61 THI group, was considered as to 69 THI group by rising up the temperature to 21.97 ± 0.18 ºC. The group previously considered as 66 THI group was accepted as 76 THI group by rising up the temperature to 28.06 ± 0.02 ºC. Feed consumption and egg weight were significantly decreased, in 69 and 76 THI groups. Daily egg production was lower in 61 and 66 THI groups than that in 69 THI group. In 76 THI group, shell weight and yolk height, were decreased. High THI caused negative effects on feed consumption, egg weight, egg quality and feed conversion ratio.

Insight into the Gut-Brain Axis and the Productive Performance and Egg Quality Response to Kudzu Leaf Flavonoid Supplementation in Late-Laying Hens.

(1) Background: Improving feed efficiency and the vitality of the reproductive system in the late stage of the egg-laying period is of great significance for prolonging the egg-laying cycle and improving egg quality. In the present study, a new flavonoid, which was extracted from kudzu leaf, was chosen to investigate its effects on the productive performance and egg quality of late-laying hens. (2) Methods: A total of 360 500-day-old Hy-Line Brown layer hens were randomly divided into a control treatment group (no KLF supplementation), and groups that received 0.2%, 0.4%, 0.6%, 0.8%, and 1.0% KLF supplement treatments. Each treatment contained 6 replicates, with 10 hens in each replicate. Productive performance metrics, including the daily egg production, egg weight, the number of deformed eggs, egg quality, egg density, egg shape index, eggshell strength, yolk color, and the Haugh unit, were meticulously recorded for each replicate. Furthermore, microbial communities and hypothalamus gene expressions were investigated based on the results of the productive performance and egg quality. (3) Results: KLF supplementation significantly decreased the deformity rate while significantly increasing the eggshell strength in the finishing phase afterward (p < 0.05). Specifically, hens supplemented with 0.6% KLF possessed the lowest deformed egg rate. KLF supplementation significantly increased the relative abundances of Bifidobacterium sp., Blautia sp., Lactococcus sp., and Lactobacillus sp., while significantly decreasing Parasutterella sp. and Escherichia-Shigella sp. (p < 0.05). Furthermore, the interactive analysis showed the hypothalamus gene expression mainly interacted with probiotics, such as Bifidobacterium sp. and Lactobacillus sp., through ribosome biogenesis, nucleocytoplasmic transport, and cAMP signaling pathways. (4) Conclusions: The findings of the present study indicate that KLF supplementation significantly proliferated probiotics, such as Bifidobacterium and Lactobacillus, which may have further interacted with hypothalamus genes, thus decreasing the deformity rate while increasing eggshell strength in the finishing phase.

Effects of Inclusion of Mango Peel Waste in Diets of Layer Chickens on Performance and Egg Quality in Kenya

Alternative ingredients for the manufacture of poultry feeds need to be identified to meet the growing demand. A 42-day feeding trial was conducted to investigate the effects of the inclusion of mango peel waste in layer chicken diets on performance and egg quality. This study involved one hundred and fifty Isa Brown layer chickens aged 60 weeks. These chickens were assigned to five treatments with graded levels of mango peels: 0% (Treatment 1), 3.5% (Treatment 2), 7% (Treatment 3), 14% (Treatment 4) and 28% (Treatment 5), using a completely randomized design (CRD). Daily egg production was recorded, and weekly measurements included feed intake, specific gravity, egg weight, shell weight and shell thickness. Notably, Treatment 5 exhibited the highest feed conversion ratio (3.09) and Roche yolk color (RYC) fan score (14.3), which was significantly (p &lt; 0.05) different from Treatment 1, with values of 2.36 and 12.4, respectively. Layer chicken fed on T1 had the highest egg weight and egg thickness (6.6 g and 0.44 mm, respectively), differing significantly (p &lt; 0.05) from Treatment T5 eggs (6.3 g and 0.41 mm). It was concluded that mango peels could substitute maize in layer chicken diets up to 7% without affecting production and egg quality. Mango peels are recommended for partial substitution of maize in layer chicken diets and as natural egg yolk pigment to impart the yellow yolk desired by consumers.

Effects of dietary supplementation of polysaccharide from Agaricus blazei Murr on productive performance, egg quality, blood metabolites, intestinal morphology and microbiota of Korean quail.

This study aimed to investigate the effects of dietary supplementation with Agaricus blazei polysaccharide (ABP) at varying concentrations on the performance, egg quality, blood biochemistry, intestinal morphology, and microflora of quail. The study involved a total of 2,700 Korean quails, which were randomly divided into three groups. The measured variables encompassed productive performance, egg parameters, carcass parameters, serum metabolites, immune response parameters, antioxidative properties, and gut microbiome. The addition of ABP did not have a significant effect on average daily feed intake. However, it was found to increase the average daily egg weight and egg production rate, reduce the feed-egg ratio. There were no significant impacts on egg quality measures such as egg shape index, egg yolk index and color, egg yolk and protein content. However, ABP supplementation significantly increased the Hough unit (p<0.01) and decreased the rate of unqualified eggs (p<0.01). Regarding serum parameters, the inclusion led to an increase in total protein concentration (p<0.05) and a reduction in low-density lipoprotein cholesterol (p<0.05). There were no significant effects observed on immune indicators such as immunoglobulin A (IgA) and IgM. ABP supplementation increased the levels of serum antioxidant indicators, including glutathione peroxidase, total superoxide dismutase (p<0.05), and total antioxidant capacity colorimeter (p<0.05). Furthermore, ABP supplementation significantly elevated the intramuscular fatty acid content in quail meat. Additionally, ABP supplementation demonstrated a significant improvement in the diversity of gut microbiota and induced alterations in the composition of the gut microbiota. The findings of this study indicate that dietary supplementation of ABP enhanced production performance and antioxidant capacity while increasing the levels of polyunsaturated fatty acids in quail muscle.

A Bayesian spatially explicit estimation of daily egg production: application to anchovy in the Bay of Biscay

Biomass estimates of fish resources by the daily egg production method (DEPM) are sensitive to the high variability of the daily egg production ( P0) and egg mortality (Z) in space. This work presents a Bayesian approach to estimate these parameters. A prior distribution of Z based on literature serves to overcome the biologically implausible Z estimates that can result from frequentist approaches. In addition to the classical estimation of a single P0 over the spawning area, the Bayesian framework allows also the modelling of egg densities in space, by including either spatial random effects, smoothing functions, or kriging like models, providing insights into the spatial variability of P0. The Bayesian approach was applied to the Bay of Biscay anchovy DEPM surveys. Results showed that this Bayesian approximation solved the implausible Z problem resulting in tighter credible intervals of both P0 and Z. Overall, spatial models outperformed the non-spatial model in terms of goodness of fit and resulted in slightly different total production estimates across models for each year, with a moderate decrease on uncertainty estimates.

Budidaya Biokonversi Larva Black Soldier Fly (BSF) dan Puyuh Petelur dalam Pengolahan Sampah Organik untuk Pelestarian Lingkungan pada Tempat Pemrosesan Akhir (TPA) Desa Pacul Kabupaten Bojonegoro

The use of BSF fly larvae using the Bioconversion method in landfills Pacul as organic waste decomposing organisms is a breakthrough for processing organic waste. The advantage of using BSF technology is that it can help reduce the amount of organic waste by up to 80%.. After the maggot is large because it decomposes waste, it can be used as the main feed in raising laying quails. Maggot can be highly nutritious animal feed because it contains substances needed by the growth and development of livestock, especially quail. But the effect was not significant on daily egg production, feed consumption, meat weight and feed conversion of laying quails. Maggot also has the ability to use quail droppings as food which makes him grow big and can be used as a good feed ingredient in living conditions. Maggot is the right solution for livestock, considering the high price of manufactured feed.

Using low-protein diet in egg production for win-win of productivity and environmental benefits should be prudent: Evidence from pilot test

A shortage of feed protein resources restricts poultry productivity. Key strategies to alleviate this problem include improvements to the structure of the gut microbiota by the appropriate intake of high-quality protein, improvements to the comprehensive protein utilization rate, and reducing the consumption of protein raw materials. In addition, damage to the environment caused by nitrogen emissions needs to be reduced. The aim of the study was to evaluate the effects of dietary protein levels on laying performance, host metabolism, ovarian health, nitrogen emissions, and the gut microbial structure and function of laying hens. In total, 360 hens at the age of 38 weeks were randomly allotted four treatments. Each of the groups consisted of nine replicates, with 10 birds per replicate, used for 12 weeks of study. Dietary protein levels of the four groups were 13.85 %, 14.41 %, 15.63 %, and 16.30 %. Results revealed that, compared with the 13.85 % crude protein (CP) group, the 15.63 % CP group experienced significantly enhanced final body weight, average daily gain, egg production, and egg mass. Compared with the 16.30 % CP group, the other groups' serum concentrations of immunoglobulin G (IgG) and immunoglobulin M (IgM) were significantly reduced. Compared with the 16.30 % CP group, the 13.85 % and 15.63 % groups had increased CP utilization rates but reduced nitrogen emission rate, and daily per egg and per kilogram egg nitrogen emissions rose with increased dietary protein levels. Compared to the 13.85 % and 14.41 % CP groups, the 16.30 % CP group exhibited a significant increase in the expression of genes related to amino acids and carbohydrate metabolic pathways. According to the linear discriminant analysis effect size diagram, the predominant bacteria in the 15.63 % CP group (e.g., Subdoligranulum, and Ruminococcaceae_UCG-013) were significantly related to CP utilization. The results of this study emphasize that production performance is significantly reduced when protein levels are too low, whereas too high protein levels lead to gut microbiota imbalance and a reduction in the utilization efficiency of nutrients. Therefore, on the premise of ensuring the health of hens, the structure of the gut microbiota can be improved by appropriately reducing protein levels, which helps to balance the relationships among host health, productivity, resources, and the environment.

Comparison of hen performance and mortality of commercial layer flocks by Strain and cage type

This study compared the egg production, defective egg rate, and mortality of commercial laying hens based on strain and cage type under commercial farm conditions. Two commercial white egg-laying strains (Hy-line and Super Nick) and two brown egg-laying strains( Nick Brown) were housed in conventional (32409 cm2) and enrichable (7200 cm2) cage systems. These layer flocks were visited weekly from 18 to 56 weeks of age, and data were collected on daily egg production, mortality, and the number of dirty and cracked eggs. Both the strain and cage type significantly affected hen-day and hen-housed egg production. Egg production was higher in conventional cages and for brown egg strains. The strain's impact on weekly mortality became insignificant after 32 weeks, while the highest mortality rates were observed in the enrichable cages. Significant differences were in the weekly dirty and cracked egg rates between layer strains and cage types. For enrichable cages and white-laying strains, the rate of dirty and cracked eggs was higher. The interaction of strain and cage type affected egg production, the rate of cracked and dirty eggs, and mortality. As a result, the brown egg-laying strain hens exhibited higher egg production than the white strain hens, and in overcrowded and enrichable that is non-enriched cages, lower egg production, higher mortality rates, and a higher rate of dirty and cracked eggs were observed.

Effect of rosemary (Rosmarinus officinalis) leaf meal supplementation on production performance and egg quality of laying hens

This experiment was conducted to investigate the supplemental effect of rosemary leaf meal (RLM) on egg production and egg quality in Lohmann-Brown laying hens. For each treatment, six replicates were performed with four 24-week-old laying hens for a total of 96 chickens. Dried rosemary leaf meal (RLM) was present in the commercial laying hen ration at 0, 1.7, 3.5 and 5.2%, respectively. The interactions between dietary treatments, egg storage temperatures (4 °C, 21.5 °C), and egg storage durations (7, 14, 21, 28, and 35 days) were examined in factorial designs using a fully randomized design. The data were analyzed using the Statistical Analysis System (SAS, 2014, Ver. 9.3) and Tukey's multiple range tests to separate the means. The inclusion of dried RLM at a level of 5.2% (p < 0.05) significantly improved the hens' daily egg production (78.9%). Feed conversion ratio (2.25) and egg weight (56.7 g) compared to control treatment. Similarly, at 3.5% and 5.2% RLM supplementation, eggshell weight (5.876 g) and eggshell strength increased significantly (p < 0.05) (compared to control, a weight of 3.76 kg/cm2 and a shell thickness (0.37 mm) was observed. In addition, the groups fed 5.2% RLM had significantly higher albumin weight (34.9 g/L), albumin height (6.9 mm), and yolk weight (15.6 g/L). l), yolk height (15.9 mm), yolk color (5.3 points), and Hough unit (83.9 points) than the control groups. Regarding the external characteristics of stored eggs, a group of hens fed at rates of 3.5 and 5.2% RLM showed significantly greater (p < 0.05) egg weight with increases in storage temperature and duration as a control group. There was a significant interaction effect between stored eggs collected from the supplemented groups in terms of egg weight, weight loss, shell weight, shell strength, and shell thickness stored at specific temperatures and storage durations. There was a decrease in albumen level and Haugh unit (HU) with an increase in storage temperature and duration over treatment (P < 0.05). Therefore, better external quality was observed in eggs collected from a group of chickens fed 4.5 and 5.2% RLM after 35 days of storage compared to a control group. Mean albumen height, albumen weight, HU, yolk height, and yolk color of eggs stored in the refrigerator (4 °C) were an exception for yolk weight, which was higher compared to room temperature (21.5 °C). Significantly low (P < 0.05) albumen height (6.61 to 2.96 cm), Hough unit (82.49 to 47.64 points), and yolk height (14.66 to 12.35 mm) were observed at 35 days storage recorded in the control group. In conclusion, supplementation with RLM at 3.5% and 5.2% improved the performance and quality of both fresh and stored eggs.

Effects of temperature on the fecundity and longevity of Zeugodacus cucurbitae (Coquillet) (Diptera: Tephritidae) on artificial diet

AbstractThe melon fruit fly, Zeugodacus cucurbitae (Coquillett), is an important polyphagous pest that damages to various agricultural crops, whose distribution has become global as a result of human activity. In this study, we investigated the fecundity, pre‐oviposition and oviposition periods, and the longevity of adult Z. cucurbitae at various constant temperatures ranging from 15 to 35.2°C. One newly emerged one virgin female and two males of Z. cucurbitae were used, and the longevity of both sexes and the fecundity of the females were examined daily. The longevity of female Z. cucurbitae ranged from 183.8 days at 15.0°C to 30.8 days at 35.2°C, and the maximum fecundity per female was 1204 eggs at 24.5°C. The lower development threshold (LDT) and thermal constant (K) of females were estimated as 14.8°C and 781.13 degree‐days, respectively. Female reproduction was modeled using a two‐phase oviposition model. Oviposition was estimated using females in the oviposition phase, which had a complete pre‐oviposition phase. The oviposition model consisted of two reproductive components (total fecundity and age‐specific cumulative oviposition rate during oviposition) and a survival component (age‐specific survival rate). The daily egg production of Z. cucurbitae was estimated in relation to adult age and temperature.

Effect of cage space allowance on egg production, egg quality, immune responses and anti-oxidant variables in White Leghorn layers

A comprehensive study was conducted to optimise cage space allowance (CSA) for White Leghorn (WL) layers (65-80 weeks of age). For the purpose, a total of 900 layers were housed in California colony cages in an open sided poultry house at three different CSA (422, 563, 844 cm2/bird). Each of the CSA was studied with 20 replicates. The daily egg production (EP), feed intake (FI), feed efficiency (FE, FI/egg mass) and egg quality traits were recorded at the end of each 28d interval. Anti-oxidant responses like lipid peroxidation (LP) and glutathione peroxidase, glutathione reductase and superoxide dismutase in blood were measured at 80 weeks of age. Similarly, the antibody titres against ND vaccine and cell mediated immune response (CMI) against PHA- P were measured at 80 weeks of age. The variation in CSA did not influence EP, egg mass, weight gain and egg shell thickness. The FI reduced and FE improved with reduction in CSA. However, the egg density and egg shell percentage increased with increase in CSA. The LP was higher and the activities of anti-oxidant enzymes were lower at 422 cm2/bird as compared to the higher space allowances. No effect of CSA on ND titre was observed, while the CMI response was higher at 844 cm2/ bird than the other two CSA. It could be concluded that, though the FE was better at 422 cm2/b, the trends of shell quality traits and antioxidant variables indicated 546 cm2/bird as requirement for WL layers in open sided poultry house under tropical regions.

Large sardine resource discovered off south-eastern Australia: Potential risks, challenges and benefits of establishing a new fishery

This paper documents the discovery of a large sardine (Sardinops sagax) resource off South-eastern Australia. We use information from three ichthyoplankton surveys for jack mackerel to apply the Daily Egg Production Method (DEPM) to the South-eastern sardine stock. Mean daily egg production was estimated from survey data. Spawning area was estimated from the surveys and using a habitat suitability model to predict presence/absence of eggs in unsurveyed areas. Spawning biomass was calculated using adult parameters from the adjacent Southern stock. The spawning biomass in the area surveyed was 262,564 t (95% CI 125,670–326–438 t). Habitat modelling using a conservative threshold suggested that the total spawning biomass was 346,388 t (95% CI 143,936–548,840 t). These results suggest this stock has the capacity to sustain an annual catch of several tens of thousands of tonnes, which is considerably larger than the recent catch of < 2500 t. Our findings provide further evidence that opportunities exist to increase Australia’s fisheries production. Risks and challenges associated with establishing a new large-scale sardine fishery, including bycatch and ecological impacts, and opposition from conservation groups and recreational fishers are discussed. We also outline the potential socio-economic and environmental benefits, including the use of marine protein and oil from a sustainable local source with low environmental impacts as an input to the AU$1.3B Tasmanian salmon aquaculture industry. We emphasize the need to adopt a precautionary approach to developing a new fishery and the critical importance of conducting comprehensive surveys to confirm our findings and inform ongoing management.

Mitigation of heat stress effects on laying hens' performances, egg quality, and some blood parameters by adding dietary zinc-enriched yeasts, parsley, and their combination.

Finding natural, handy and efficient nutritional solutions to prevent and mitigate negative effects caused by environmental heat stress and to be applied to large-scale laying hen industry. A 3-weeks trial was conducted on 128 laying hens TETRA-SL LL (50 weeks of age) housed in 8 cages/group, 4 laying hens/cage, 32 laying hens/group, under heat stress conditions (34±1°C). The basal diet on corn and soybean meal was formulated to be isocaloric and isonitrogenic. Compared to Control group diet (C), experimental groups E1 included 1% zinc-enriched yeast; E2 included 2% parsley and E3 included 1% zinc-enriched yeast combined with 2% parsley to minimize the heat stress effects. The parsley and the zinc-enriched yeast were analysed for their chemical composition, total polyphenols, antioxidant capacity, minerals, vitamin E and incorporated into the ration structure. Production parameters, egg quality, biochemical and haematological profiles of blood samples were analysed during the trial. A statistically significant (p < 0.05) average egg weight was noticed on E2 and E3 compared to Control group, and also during the 1st week compared to the 2nd and the 3rd experimental weeks. Average daily feed intake values were highly significant (p < 0.001) on E3 group compared to C, E1, E2, and on the 2nd week compared to the 3rd experimental week (p < 0.021). Feed conversion rate was highly significant (p < 0.001) during the 2nd and the 3rd experimental weeks compared to the 1st week. The average daily egg production was highly significant (p < 0.001) within 1st week compared to the 2nd and 3rd weeks. A highly significant (p < 0.001) yolk coloration was noticed on E2 and E3 groups. The malondialdehyde (MDA) concentration decreased significantly (p < 0.05) to all experimental groups compared to Control group during the 14th and 28th days of storage. These findings suggest that the two ingredients minimized the heat stress effects on production performance parameters with a demonstrated antioxidant capacity role by delaying the lipid peroxidation during different storage time periods.

Effect of Supplementing Eucalyptus (Eucalyptus globulus) Leaf Powder on Average Weekly Feed Intake and Egg production of Commercial Laying Hens

The present experiment was designed to study the effect of dietary incorporation of eucalyptus leaf powder on the average weekly feed intake and egg production of commercial laying hens. A 12-week feeding experiment was conducted on 72 White Leghorn laying chickens of 28 weeks of age. Hens were randomly assigned to one of four treatment groups, each having 18 birds and three replicates of six birds. Four treatments were included as a control (T1): basal diet, (T2): Incorporation of 0.3% eucalyptus leaf powder in the basal diet containing phytase, (T3): Incorporation of 0.45% eucalyptus leaf powder in the basal diet containing phytase, (T4): incorporation of 0. 6% eucalyptus leaf powder in the basal diet containing phytase. Daily feed intake and egg production were recorded. The results revealed that Supplementing Eucalyptus (Eucalyptus Globulus) Leaf powder did not affect the cumulative performance of laying hens in terms of feed intake and egg production (P&gt;0.05). Based on the above findings, it was determined that adding 0.3 percent eucalyptus leaf powder to the basal diet containing phytase improves egg production. Furthermore, because Eucalyptus leaves can be procured at no cost, their incorporation is cost-effective and can help reduce feed expenditures.

Effect of Dietary Supplementation of Zinc Nanoparticles Prepared by Different Green Methods on Egg Production, Egg Quality, Bone Mineralization, and Antioxidant Capacity in Caged Layers.

The present study was planned to evaluate the effect of dietary zinc-oxide (ZnO) nanoparticles synthesized by different plant extracts on egg production, egg quality, bone mineralization, and antioxidant capacity in caged layers. Nanoparticles of ZnO were synthesized by using extracts of Allium sativum (AS), Aloe vera (AV), Curcuma longa (CL), and Zingiber officinale (ZO). Different sources of nano ZnO (AS, AV, CL, and ZO) with varying levels (35, 70, or 105 ppm) were tested on 288 caged LSL layers of 25 weeks of age. Each diet was offered to 4 replicates of 6 birds each level and the duration of trial was 8 weeks. Daily egg production, feed consumption, and fortnightly egg quality parameters were recorded. Egg quality parameters (egg weight, egg mass, shape index, yolk index, albumen index, Haugh unit score, specific gravity, and eggshell thickness) were determined fortnightly by taking 2 eggs from each replicate randomly. Antioxidant capacity and bone mineralization were determined at the end of the trial. Results showed that the nano ZnO preparations were not effective (P < 0.05) on laying performance but additional levels (70 ppm) improved egg production, feed conversion ratio, egg mass, Haugh unit score, and antioxidant capacity of chickens. An interaction was found among nanoparticles prepared by Allium sativum and Zingiber officianale extracts with 70 ppm level regarding total antioxidant capacity and egg production (P > 0.05). Interaction among source and level was not found regarding feed intake, feed conversion ratio, egg quality, bone characteristics, and concentration of Zn. Results of the present study suggest that nano ZnO sources may not be a factor that affects performance, but level affects the birds' physiology. Thus, it is concluded that nano ZnO with 70 ppm concentration is sufficient to optimize the laying performance.

Assessments of productive performance, eggshell quality, excreta moisture, and incubation traits of laying breeder hens fed a proprietary blend of Quillaja and Yucca.

A study was conducted to evaluate performance, eggshell quality, nutrient metabolizability, and incubation traits of laying breeder hens fed diets supplemented with an additive containing polyphenols and saponins of a proprietary blend from Quillaja saponaria and Yucca schidigera (QY) biomass. Hens were fed 4 feeds in 5 periods of 28 days each from 30 to 49 weeks of age. Experimental feeds were a Control diet; Control + virginiamycin (33 g/ton); Control + QY (250 g/ton) and Control + virginiamycin + QY. A total of 40 White Plymouth Rock and 44 Rhode Island Red breeder hens were allocated in individual cages using a completely randomized block design with 21 replicates. Performance parameters, evaluated per period, were egg production, egg weight, FCR, egg mass, and culled eggs. All eggs were collected in the last 4 days of each period to evaluate specific egg weight, percentage of albumen, yolk and shell, and Haugh unit as well as cuticle quality, shell strength, and shell thickness. At the end of the experiment, nutrient metabolizability assessment and four incubations were conducted. There were no interactions between diet and period in all evaluated responses (P > 0.05). Experimental diets did not affect daily egg production, egg weight, and egg mass as well as Haugh unit, yolk and albumen percentage, and yolk color (P > 0.05). However, hens fed Control + QY produced eggs with better shell strength, shell thickness, and cuticle quality than hens fed the Control (P < 0.05). Hens fed Control + QY or Control + virginiamycin + QY had lower culled eggs, better FCR and higher egg specific weight, shell percentage, and yolk strength compared to breeder hens fed the Control (P < 0.05). In general, hens fed QY achieved enhanced performance and egg quality compared to virginiamycin. In conclusion, laying breeder hens fed diets supplemented with Quillaja and Yucca additive, from 30 to 49 weeks of age, maintained their productive performance, had improved eggshell and cuticle quality and reduced culled, dirty and contaminated eggs.

Characterization of clutch traits and egg production in six chicken breeds.

The better understanding of laying pattern of birds is crucial for developing breed-specific proper breeding scheme and management. Daily egg production until 50 wk of age of six chicken breeds including one layer (White Leghorn, WL), three dual-purpose (Rhode Island Red, RIR; Columbian Plymouth Rock, CR; and Barred Plymouth Rock, BR), one synthetic dwarf (DY), and one indigenous (Beijing-You Chicken, BYC) were used to characterize their clutch traits and egg production. The age at first egg, egg number, average and maximum clutch length, pause length, and number of clutches and pauses were calculated accordingly. The egg number and average clutch length in WL, RIR, CR, and BR were higher than those in DY and BYC (p<0.01). The numbers of clutches and pauses, and pause length in WL, RIR, CR, and BR were lower than those in DY and BYC (p<0.01). The coefficient variations of clutch length in WL, RIR, CR, and BR (57.66%, 66.49%, 64.22%, and 55.35%, respectively) were higher than DY (41.84%) and BYC (36.29%), while the coefficient variations of egg number in WL, RIR, CR, and BR (9.10%, 9.97%, 10.82%, and 9.92%) were lower than DY (15.84%) and BYC (16.85%). The clutch length was positively correlated with egg number (r = 0.51 to 0.66; p<0.01), but not correlated with age at first egg in all breeds. The six breeds showed significant different clutch and egg production traits. Due to the selection history, the high and median productive layer breeds had higher clutch length than those of the less productive indigenous BYC. The clutch length is a proper selection criterion for further progress in egg production. The age at first egg, which is independent of clutch traits, is especially encouraged to be improved by selection in the BYC breed.

Expansion and contraction of the Engraulis ringens spawning area in northern Chile

Many studies have considered the temporal patterns of reproduction of Engraulis ringens, but little attention has been given to the spatial patterns of reproduction (spawning areas), which have shown great variability in both location (geographical position) and extent (the area covered by positive stations), without a satisfactory explanation. Along the Chilean coast, the daily egg production method (DEPM) has been used for several years to estimate spawning biomass in the northern Chile E. ringens population, with 24 surveys being carried out from 1992 to 2020. The most fluctuating parameters estimated in the DEPM have been the location and extent of the spawning area and the average female weight. In the last few years the eggs were distributed near the coast, whereas in the first few years they showed a more oceanic distribution. The average female weight has fallen from 30 g in the 1990s to 11 g in the last few years. In the present study, we analysed the relationship of the location and extent of spawning areas with female size and abundancy in E. ringens from northern Chile. According to the results, periods of high abundancy of eggs are positively correlated with larger females that spawn in more oceanic zones and to the south, expanding the spatial egg distribution and increasing the egg density. By contrast, in years with low abundance of eggs, the spawning was located north and towards the coast, with a smaller spawning area and smaller female size.

The use of protein and other biologically active substances in feeding honey bees

In the presented work, the issue of the use of protein feeds with biologically active additives to increase the nutritional value of artificial feeds is considered. This approach makes it possible to introduce various sources of protein, amino acids, vitamins into the bee feed, as well as enzymes to relieve the load on the bee's body for digesting substances, growth-stimulating drugs based on organic acids, etc. Experiments conducted in 2018 on feeding candi bees to the composition, which included isolated soy protein, apple cider vinegar, showed the following results. In the control group, bees actively ate top dressing, however, in some bee families, the presence of yellowish-brown liquid excrement was noted, which indicated the presence of nosematosis. Bees from the experimental groups also actively consumed candi, but with the addition of soy isolate and apple cider vinegar, while the frames were clean, there were no spots of diarrhea and podmore. The Federal Scientific Center of Beekeeping is conducting research on the development of various formulations of feedings for honey bees. For the approbation of carbohydrate feeds with the inclusion of enzyme compositions in them, appropriate studies were conducted. 3 experimental groups were formed on the principle of pairs of analogues. The control group received sugar syrup, the first – inverted syrup, and the second group - inverted syrup enriched with flower pollen fermentolysate. Feeding of the presented feedings had an impact on the flight activity of bee colonies. Thus, the control group had the lowest flight activity. In the experimental groups, the flight activity of bee colonies was higher. In addition to the flight activity of bee colonies, the average daily egg production of queens was studied. In the control group, the average daily egg production of the uterus was at the level of 550 eggs. In the first experimental group, the uterine egg production was 9.10% higher compared to the control, and in the second group by 20.0%.

Effects of salinity on survival, reproductive performance, population growth, and life stage composition in the calanoid copepod Acartia bilobata

Copepods are a critical live prey item for most marine finfish larvae in the natural environment. The calanoid copepod belonging to species Acartia is a potential live food for the larval rearing of marine finfishes because of their higher productivity and tolerance to wide range of salinities. The present study was conducted to determine the effect of salinity on production parameters to standardize the optimal salinity for Acartia bilobata culture. For selecting the optimal salinity range, the adult copepods were exposed to abrupt salinity change from 30 g L−1 to ten salinity levels, including 0, 5, 10, 15, 20, 25, 30, 35, 40 and 45 g L−1 and their survival estimated after 24 h. Further, the effect of salinity (15, 20,25,30, and 35 g L−1) on egg production, hatching success and population growth were studied. Following sudden salinity change, A. bilobata could tolerate a wide range of salinities from 15 to 35 g L−1, and no copepod survived below 10 g L−1 and above 35 g L−1. Average daily egg production was significantly higher at 25 and 30 g L−1 (32 ± 1 and 34 ± 2 eggs female−1 day−1). A remarkably low egg hatching success was recorded at 15 g L−1 salinity; however, all other tested salinities showed similar egg hatching success. Different salinity levels did not affect the sex ratio of A. bilobata. A significantly higher total population number (1539 ± 75) and intrinsic population growth rate (0.50 ± 0.00) was observed at 30 g L−1, followed by 25 g L−1 salinity. The lowest mean population (518 ± 19) and population growth rate (0.39 ± 0.00) were recorded at 15 g L−1 salinity. The study results suggested that 25–30 g L−1 is the optimal salinity range to achieve maximal production of A. bilobata.