Effect of thermal manipulation on embryonic development, hatching process, and chick quality under heat-stress conditions

Thermal stress is a risk that threatens poultry welfare and productivity. Thermal manipulation during egg incubation is considered a prevention strategy used to mitigate the detrimental effects of high ambient temperatures on birds. This study aimed to investigate the impact of thermal manipulation, applied to chicken breeder's eggs during the incubation period, on embryonic development, hatching characteristics, and chick quality, as well as posthatch thermotolerance and performance. A total of 1,200 fertile eggs were randomly and equally assigned into 2 groups of 3 replicates (200 eggs/replicate), using a randomized experimental design followed by t test. The first group eggs (G1) were subjected to a commercial setter temperature of 37.5°C with 55% relative humidity (RH) throughout the incubation period (1-18 d) and served as a control, while the second group eggs (G2) were treated the same commercial setter conditions until the 11th day of the incubation, then the eggs were exposed to a higher temperature of 39.5°C with 60% RH for 4 h daily from the 12th to the 18th day of incubation. All eggs in both groups were exposed to the same temperature condition of 37.2°C with 70% RH from the 19th to the 22nd days of the incubation (hatching period). Three hundred hatched female chicks per each treatment group were transferred into a closed-system house and distributed randomly into 20 floor pens (15 birds per pen). At the 8th week of age, birds were exposed to a daily heat challenge by raising the temperature to 35°C for 6 h until the 18th week of the chick's age. According to the results, thermal manipulation at 12 to 18 d of egg incubation positively (P ≤ 0.05) affected several studied traits. It improved some embryonic development traits, such as embryonic weight and tibia length, as well as some hatching parameters, such as hatching time and pipped eggs. It also improved hatched chick quality traits, including the chick's weight, length, and activity. In addition, it enhanced the posthatch chick's thermotolerance and body weight. Hatched chicks of G2 had significantly (P ≤ 0.05) higher total protein, albumin, IgM, glucose, calcium, total antioxidant, and T3 than G1 chicks. They also had significantly (P = 0.001) higher body weight (23%) at the 18th week of age than G1, as well as a lower feed conversion ratio (20.71%) than G1 chicks at 8 to 18 wk of age. Therefore, it is recommended to apply thermal manipulation during egg incubation, particularly at 12 to 18 d, for its positive effects on the pre- and posthatch performance.

Bee Products for Poultry and Rabbits: Current Challenges and Perspectives

Poultry and rabbit production are important and rapidly growing agricultural subsectors, particularly in several developing countries. To ensure the sustainability of poultry and rabbit production, realistic poultry and rabbit farming practices must be improved. Apitherapy is a traditional alternative medicine that involves the prevention and treatment of some diseases with several bee products including propolis, royal jelly, pollen, and venom. More feeding investigations on the numerous benefits of bee products for poultry and rabbits are crucial to be addressed. Poultry and rabbit production has recently experienced numerous challenges, including climate change, disease spread, and antibiotic misuse. Improving animal welfare, health, and production is a top priority for all livestock farms, as is supplying consumers with safe and healthy products. Therefore, this review aims to collect and investigate recent relevant literature on the use of bee products, as feed additives, drinking water supplements, and injections, for poultry and rabbits to improve animal health and production. From the current findings, bee products can improve the growth and immunological performance of small-livestock animals, such as poultry and rabbits, by activating digestive enzymes, maintaining microbial balance, and promoting vitamin synthesis. Therefore, bee products could be a promising natural alternative to growth promoters, reproductive stimulants, and immunological enhancers in poultry and rabbit farms to provide safe and healthy products for humans.

Influence of non-ventilating intervals during early incubation stage on egg hatching process

Background and Aim

The exchange of oxygen and carbon dioxide (CO2) in the incubator plays a key role in embryonic development and hatching. This study aimed to study the effect of non-ventilated (NV) intervals during the early stage of embryonic development on the hatching process.

Materials and Methods

Hatching eggs (n = 7200) were equally divided into four treatment groups and incubated in four incubators. The first group was incubated in normal ventilated condition (V) during the setting phase of incubation. Ventilation holes of the three remaining incubators were closed for the first 3, 6, and 9 days and termed as NV groups (NV1, NV2, and NV3, respectively). A gradual increase in CO2 was allowed for NV groups, followed by opening the incubator holes to permit ventilation throughout the rest of the incubation periods.

Results

Obtained results demonstrated that CO2 concentration gradually increased up to 0.19% for the NV1 group, 0.41% for the NV2 group, and 0.90% for the NV3 group, while CO2 concentration remained at 0.08% during the first 9 days of incubation in the V group. Albumen pH was lowered for all NV groups. The highest hatchability percentage was recorded for NV3 followed by NV2 and NV1 groups. All NV groups represented earlier and narrower spread of hatch and higher hatched chick weight. Embryos and hatched chicks in the NV groups had higher hormonal levels of thyroxin and corticosterone.

Conclusion

All non-ventilation periods had positive effects on narrowing the spread of hatch, increasing hatched chick weight and hatchability percentage compared to the normal V condition. Furthermore, the non-ventilation throughout the first 9 days of incubation yielded the best hatching results.

Could Insect Products Provide a Safe and Sustainable Feed Alternative for the Poultry Industry? A Comprehensive Review

The planet is home to more than 2000 species of edible insects, some of which have been consumed as food for many years. Recently, edible insect products have been gradually increasing in several countries, such as Italy and Egypt, as novel feed resources for humans and animals due to their availability, potential economic benefits, and high nutritive value. The insect industry can provide a new solution for livestock nutrition and offer many additional advantages, but there are obstacles to overcome, such as some nutritional organizations that forbid its usage. Nevertheless, previous research indicates that different insect species could be used safely as nutraceuticals in poultry farming to improve broiler growth performance (>3%) and layer egg production (>5%). Among these species, there are various products and extracts that can be used in poultry nutrition in a sustainable manner. This review provides an outline of insect composition, nutrient values, application in poultry feed, safety, and guidelines, and finally, the future perspectives of insects as an alternative feed source in poultry diets.

Application of botanical products as nutraceutical feed additives for improving poultry health and production

Poultry is one of the most consumed sources of animal protein around the world. To meet the global demands for poultry meat and eggs, it is necessary to improve their nutrition to sustain the poultry industry. However, the poultry industry faces several challenges, including feedstuff availability, the banning of antibiotics as growth promoters, and several environmental stressors. Therefore, there is a critical need to include available nutraceuticals in the diet to sustain the poultry industry. Nutraceuticals are natural chemical substances that positively influence animal physiological and productive traits. Botanical products (such as fenugreek seeds, ginger roots, and olive leaves) are among the most commonly used nutraceuticals and are gradually gaining popularity in the poultry industry due to their immense benefits in nutrition and therapeutic properties. They can be added to the diet separately or in combination (as a natural antioxidant and immunostimulant) to improve poultry health and production. Botanical products are rich in essential oils and essential fatty acids, which have multiple benefits on the animal's digestive system, such as activating the digestive enzymes and restoring microbiota balance, enhancing poultry health, and production. These nutraceuticals have been shown to stimulate the expression of several genes related to growth, metabolism, and immunity. In addition, the essential oil supplementation in poultry diets up-regulated the expression of some crucial genes associated with nutrient transportation (such as glucose transporter-2 and sodium-glucose cotransporter-1). Previous studies have suggested that supplementation of botanical compounds increased broiler body weight and hen egg production by approximately 7% and 15%, respectively. Furthermore, the supplementation of botanical compounds enhanced the reproductive efficiency of hens and the semen quality of roosters by 13%. This review article discusses the significant effects of some botanical products in the poultry industry and how they can benefit poultry, especially in light of the ban on antibiotics as growth promoters.

Nutritional significance and health benefits of omega-3, -6 and -9 fatty acids in animals

The balance between omega-3 (ω-3), omega-6 (ω-6) and omega-9 (ω-9) fatty acids (FAs) is very important because these types of oils constitute essential components for the formation of the cell membrane, also they are precursors for a large number of substances in the body. One of the most important strategies for improving the increment of polyunsaturated FAs in poultry and animal meat is the dietary administration of these FAs. Additionally, the different sources of ω-3 or 6 in the diet improve the performance, public health and physiological aspects including anti-oxidative properties and immunity. ω-3 FAs have anti-inflammatory characteristics due to their ability to reduce cytokines liberation. High-level of ω-6 FAs is always associated with an increased incidence of dangerous disorders like depression and heart disease. These FAs showed a tremendous series of beneficial impacts like improved cholesterol levels and a decreased occurrence of coronary heart diseases. This article includes some information on the use of ω-3, ω-6 and ω-9 FAs in animal and human diets. These oils are vital for the physiological and health aspects, and the information mentioned here will improve our understanding of the functions and roles of these FAs in the body.

Advanced Practical Strategies to Enhance Table Egg Production

The global demand for table eggs has increased exponentially due to the growing human population. To meet this demand, major advances in hen genetics, nutrition, and husbandry procedures are required. Developing cost-effective and practically applicable strategies to improve egg production and quality is necessary for the development of egg industry worldwide. Consumers have shown a strong desire regarding the improvement of hens' welfare and egg quality. They also become interested in functional and designer foods. Modifications in the nutritional composition of laying hen diets significantly impact egg nutritional composition and quality preservation. According to previous scientific research, enriched egg products can benefit human health. However, producers are facing a serious challenge in optimizing breeding, housing, and dietary strategies to ensure hen health and high product quality. This review discussed several practical strategies to increase egg production, quality, and hens' welfare. These practical strategies can potentially be used in layer farms for sustainable egg production. One of these strategies is the transition from conventional to enriched or cage-free production systems, thereby improving bird behavior and welfare. In addition, widely use of plant/herbal substances as dietary supplements in layers' diets positively impacts hens' physiological, productive, reproductive, and immunological performances.

Potential role of important nutraceuticals in poultry performance and health - A comprehensive review

Antibiotics use in poultry as a growth promoter leads to the propagation of antibiotic-resistant microorganisms and incorporation of drug residues in foods; therefore, it has been restricted in different countries. There is a global trend to limit the use of antibiotics in the animal products. Prevention of the antibiotics use in the poultry diets led to the reduction in the growth performance. Consequently, there is a high demand for natural substances that lead to the same growth enhancement and beneficially affect poultry health. These constituents play essential roles in regulating the normal physiological functions of animals including the protection from infectious ailments. Nutraceuticals administration resulted beneficial in both infectious and noninfectious diseases. Being the natural components of diet, they are compatible with it and do not pose risks associated with antibiotics or other drugs. Nutraceuticals are categorized as commercial additives obtained from natural products as an alternative feed supplement for the improvement of animal welfare. This group includes enzymes, synbiotics, phytobiotics, organic acids and polyunsaturated fatty acids. In the present review, the summary of various bioactive ingredients that act as nutraceuticals and their mode of action in growth promotion and elevation of the immune system has been presented.

Improving the reproductive, immunity and health status of rabbit does using honey bee venom

The aim of the present study was to investigate the long-term effect of using bee venom (BV) on the reproductive performance, immune, and health status of rabbit does and its effect on their litters. Sixty mature does, from Spanish V-line rabbit stock, were randomly assigned to four homogeneous groups with 15 does each. The 1^st , 2^nd and 3^rd groups were injected twice weekly under the neck skin with 0.1 ml solution contains 0.1, 0.2 and 0.3 mg BV/rabbit respectively. The 4^th group served as a control group. From the results, litter size at birth, litter weight and survival rate at weaning age as well as milk yield were significantly (p ≤ 0.05) increased in BV groups than in the control group. Serum estradiol 17-β (E2) was significantly (p ≤ 0.05) higher (15%) in the rabbit does treated with BV compared to the control group. The treated does with BV at any study doses showed a gradual and significant (p ≤ 0.05) decrease (12%) in serum progesterone levels (P4) compared to the control. They also showed a significant (p≤0.05) increase in conception (17%) and fertility rates (10%) compared to the control does. Treatment of rabbit does with BV caused a gradual and significant (p ≤ 0.05) reduction in both aspartate aminotransferase (AST) (16%) and alanine aminotransferase (ALT) (37%) liver enzyme activities. Additionally, results have shown that BV resulted in a gradual and significant (p ≤ 0.05) increase in total antioxidant capacity (TAC), antioxidative enzymes such as glutathione S-transferase (GST) and glutathione peroxidase (GPx), serum IgG, IgM and IgA levels with significant (p ≤ 0.05) decrease in malondialdehyde (MDA) and thiobarbituric acid reactive substances (TBARS) in BV groups compared to the control group. Results suggest that BV can be used in rabbit farming as an effective and safe alternative to artificial chemical drugs (sexual-stimulants) to improve certain reproductive traits, immune response and health.

Crossing effect for improving egg production traits in chickens involving local and commercial strains

Aim

This study aimed to contribute to the productivity improvement of the local chickens by enhancing their egg production traits using a crossbreeding program between Alexandria (local strain) and Lohmann White (commercial strain).

Materials and Methods

One thousand two-hundred and eighty-five 4-week-old chicks from two strains: Alexandria local strain (AA) and Lohmann White commercial strain (LL) and their reciprocal crosses obtained from 16 males and 160 females, were used to produce four genetic groups (AA, LL, AL, and LA). Differences among genotypes, direct additive, heterosis, and reciprocal effects were investigated regarding the following traits: Body weight at 4 and 8 weeks and at the age of sexual maturity, age at sexual maturity, egg production, average egg weight, and egg mass during the first 90 days of laying.

Results

Statistically significant effects of the genotypes were observed on traits studied. Analysis of direct additive effects showed that AA was superior as a sire strain for improving body weight at early age. For egg traits (age at sexual maturity, egg production, average egg weight, and egg mass), LL was better as a sire strain to improve these traits. Significant positive heterosis percentages were observed for body weight. The crosses (AL and reciprocal) were significantly superior in egg traits (egg production, average egg weight, and egg mass) compared to the local strain. The cross (LA) laid significantly earlier than the local strain. Analysis of reciprocal effects cleared that the local strain could be used as a strain of dam to improve body weight and egg traits.

Conclusion

Crossing improved egg production, egg weight, and egg mass in hybrids compared to the local strain.

Effect of carbon dioxide during the early stage of duck egg incubation on hatching characteristics and duckling performance

Gaseous exchange is very important for embryonic development during the incubation of bird eggs. The present study was carried out to investigate the effect of carbon dioxide (CO₂) pumping during the first 10 days of Pekin duck egg incubation on hatching characteristics, embryonic growth, hormonal concentrations and the post-hatch weight of the ducks. Two different ventilation conditions were used in this study. In one condition (V), the incubator was ventilated standard. In the other condition (NV), CO₂ was gradually pumped into a non-ventilated incubator to reach and maintain a 1% concentration through the first 10 days of incubation, after which the incubator was ventilated for the rest of the incubation period. The CO₂ percentage in the V incubator was constant at approximately 0.18%; by contrast, in the NV incubator, the concentration was increased gradually from 0.17% to 1%, where it was maintained through the 10th day of incubation. Throughout the incubation period, the egg weight loss and the embryonic mortality percentages were significantly lower in NV than in V. The hatchability of fertile eggs and the weights of ducklings at hatch were significantly higher in NV than in V. The embryonic T₃, T₄ and corticosterone levels in NV were significantly higher than those in V. Additionally, the haematological parameters (haemoglobin, packed cell volume and red blood cells) of the embryos were significantly higher in NV than in V. Furthermore, a total of 1198 ducklings for the V and NV conditions, all one day old, were individually weighed and then transferred into randomly assigned floor pens with 3 replicates for each ventilation condition. The feed conversion ratio of the ducks was significantly lower in NV than in V, while the reverse was true of body weight at different ages. Therefore, we can conclude that the NV condition with circulation of CO₂ for the first 10 days of incubation is preferable to the V condition.

Association of single-nucleotide polymorphism of melanocortin gene with feed intake in rabbit (Oryctolagus cuniculus)

The aim of the study was to investigate the association of two parts of melanocortin gene (MC4R-1, MC4R-2) and feed intake for V-line rabbits. V-line rabbits were grouped into high and low daily feed intake during the period from 30 to 63 days of age in order to identify MC4R SNPs useful for association study with feed intake. DNA from blood samples of each group was extracted to amplify the MC4R gene. The purified PCR products were sequenced in those had the highest and lowest feed intake. Alignment of sequence data from each group revealed that there is a variation detected in MC4R-1 at nucleotide 35 (T-G) (sense mutation) and another variation was detected in MC4R-2 gene at nucleotide 19 (T-C) (sense mutation) for high feed intake rabbits. These sense mutations lead to transform some amino acids and cause a significant change of the MC4R function. The results of average daily feed intake (ADFI) indicated that group (1) had significantly higher feed intake than group (2) of V-line rabbits. The detected mutations and the analysis of daily feed intake means revealed a significant association between MC4R polymorphism and feed intake in rabbits.

Comparison of milk production and milk composition for an exotic and a local synthetic rabbit lines

Aim:

Basic objective of this research was to compare two rabbit lines: V-line (exotic line), Alexandria (local synthetic line) for yield and composition of milk product and their effect on productive performance of rabbits.

Materials and Methods:

The experiment was conducted on 80 does and their kits. Milk yield (MY) of each doe and milk composition (MC) were recorded at 3^rd week of lactation.

Results:

The results of MY showed insignificant difference between V-line and Alexandria line. While the results of MC indicated significant differences in milk protein and fat between the two lines. The protein electrophoresis was used for assaying variation in milk proteins between the two lines. The banding protein patterns showed seven protein bands for Alexandria line and six bands for V line. The results demonstrated one specific protein marker at 48 KDa (κ-casein) in Alexandria doe’s milk. Moreover, the results of individual body weight at weaning age indicated that Alexandria rabbits had significantly higher body weight compared with V-line rabbits (845.33 g, 664.05 g, respectively). Alexandria line had significantly lower mortality rate compared with V-line (1.5%, 2.7%, respectively).

Conclusion:

The differences which obtained in Alexandria line milk may play an important role in the productive performance of rabbits.

The gene expression of weaning age and its effect on productive performance of rabbits

<p>Weaning age for mammals remains a topic of debate and an interesting subject of research. The literature data reflect opposite views on the recommended weaning age of rabbits. Thus, we determined the optimal weaning age for average commercial rabbit lines by studying one of these lines, the V-line. Gene expression of weaning age was studied in this research to reach the optimal weaning age for efficient rabbit growth and survival. The effect of weaning age on growth and mortality rates was investigated in young rabbits by comparing 3 groups (kits of 10 V-line does for each group), weaned at 23 (W23), 28 (W28) and 33 (W33) days of age. Rabbits weaned at 23 d of age had significantly (P&lt;0.05) lower body weight at the age of 63 d (market age) than those weaned at 28 and 33 d of age. The weaning age also influenced survival; mortality rate was highest in rabbits weaned at 23 d of age, followed by those weaned at 28 and 33 d of age. Morphometric parameters reflect the integral effect of all factors influencing digestive tract growth and development. From the results, it seems that the small intestine length did not have a clear effect on different weaning ages. Quantitative real-time polymerase chain reaction analysis is an important tool to monitor changes in gene expression in animals such as rabbits. We used this approach to measure intestinal insulin-like growth factor-1 (IGF-1) mRNA level and observed that the expression levels of IGF-1Ea, IGF-1Eb and IGF-1R were nearly the same in W28 and W33 rabbits, while they were the lowest in W23 rabbits. Serum IGF-1 concentrations tended to present significant differences (P&lt;0.05) with different weaning ages. We found that levels of IGF-1 in rabbits weaned at 28 and 33 d of age were convergent and higher than the IGF-1 levels in rabbits weaned at 23 d of age. Moreover, the early weaning of rabbits has a negative impact on growth. This therefore suggests that moderate weaning (28W) will be suitable for the farm economy and will improve rabbit production better than early or late weaning.</p>

Associations between single nucleotide polymorphisms in multiple candidate genes and body weight in rabbits

Aim:

In this study, we examined parts of six growth genes (growth hormone [GH], melanocortin 4 receptor [MC4R], growth hormone receptor [GHR], phosphorglycerate mutase [PGAM], myostatin [MSTN], and fibroblast growth factor [FGF]) as specific primers for two rabbit lines (V-line, Alexandria) using nucleotide sequence analysis, to investigate association between detecting single nucleotide polymorphism (SNP) of these genes and body weight (BW) at market.

Materials and Methods:

Each line kits were grouped into high and low weight rabbits to identify DNA markers useful for association studies with high BW. DNA from blood samples of each group was extracted to amplify the six growth genes. SNP technique was used to study the associate polymorphism in the six growth genes and marketing BW (at 63 days) in the two rabbit lines. The purified polymerase chain reaction products were sequenced in those had the highest and lowest BW in each line.

Results:

Alignment of sequence data from each group revealed the following SNPs: At nucleotide 23 (A-C) and nucleotide 35 (T-G) in MC4R gene (sense mutation) of Alexandria and V-line high BW. Furthermore, we detected the following SNPs variation between the two lines: A SNP (T-C) at nucleotide 27 was identified by MC4R gene (sense mutation) and another one (A-C) at nucleotide 14 was identified by GHR gene (nonsense mutation) of Alexandria line. The results of individual BW at market (63 days) indicated that Alexandria rabbits had significantly higher BW compared with V-line rabbits. MC4R polymorphism showed significant association with high BW in rabbits.

Conclusion:

The results of polymorphism demonstrate the possibility to detect an association between BW in rabbits and the efficiency of the used primers to predict through the genetic specificity using the SNP of MC4R.

Estimate the contribution of incubation parameters influence egg hatchability using multiple linear regression analysis

Aim:

This research was conducted to determine the most affecting parameters on hatchability of indigenous and improved local chickens’ eggs.

Materials and Methods:

Five parameters were studied (fertility, early and late embryonic mortalities, shape index, egg weight, and egg weight loss) on four strains, namely Fayoumi, Alexandria, Matrouh, and Montazah. Multiple linear regression was performed on the studied parameters to determine the most influencing one on hatchability.

Results:

The results showed significant differences in commercial and scientific hatchability among strains. Alexandria strain has the highest significant commercial hatchability (80.70%). Regarding the studied strains, highly significant differences in hatching chick weight among strains were observed. Using multiple linear regression analysis, fertility made the greatest percent contribution (71.31%) to hatchability, and the lowest percent contributions were made by shape index and egg weight loss.

Conclusion:

A prediction of hatchability using multiple regression analysis could be a good tool to improve hatchability percentage in chickens.

Use of inter simple sequence repeats and protein markers in assessing genetic diversity and relationships among four rabbit genotypes

<p>The importance of DNA and protein applications as powerful tools in breeding programmes is revealed. The inter simple sequence repeats (ISSR) technique was used to characterise and determine phylogenetic relationships among 4 genotypes of rabbit, namely Alexandria (Alex), V line (V), New Zealand White (NZW) and California (Cal). Six out of 7 ISSR primers exhibited sufficient variability and were used to characterise the genetic diversity and relationships among studied genotypes. A total of 141 DNA  ands were detected. DNA fragments were generated with 87 (61.7%) being polymorphic, indicating considerable genetic variation among the examined genotypes. While protein electrophoresis provides a precise method for assaying variation in serum proteins which play an important part in productive performance. The results demonstrated 2 specific protein markers in Alexandria rabbits; these specific protein markers may be responsible for the superiority of Alexandria line in weight. Phylogenetic analysis based on Nei and Li unbiased genetic distance illustrated that (Alex &amp; V) and (Cal &amp; V) were genetically closely related. Our results showed that ISSR and protein electrophoresis are useful methods to detect different genetic expressions and understand the variability in some productive traits in rabbits.</p>