Nowadays, breakthroughs in molecular biology are happening at an unprecedented rate. One of them is the ability to engineer transgenic animals. A transgenic animal is one whose genome has been changed to carry genes from another species or to use techniques for animal genome editing for specific traits. Animal features can be changed by purposefully altering the gene (or genes). A mouse was the first successful transgenic animal. Then pigs, sheep, cattle, and rabbits came a few years later. The foreign-interested genes that will be used in animal transgenic techniques are prepared using a variety of methods. The produced gene of interest is placed into a variety of vectors, including yeast artificial chromosomes, bacterial plasmids, and cosmids. Several techniques, including heat shock, electroporation, viruses, the gene gun, microinjection, and liposomes, are used to deliver the created vector, which includes the interesting gene, into the host cell. Transgenesis can be carried out in the gonads, sperm, fertilized eggs, and embryos through DNA microinjection, retroviruses, stem cells, and cloning. The most effective transgenic marker at the moment is fluorescent protein. Although transgenesis raises a number of ethical concerns, this review concentrates on the fundamentals of animal transgenesis and its usage in industry, medicine, and agriculture. Transgenesis success is confirmed by the integration of an antibiotic resistance gene, western and southern blots, PCR, and ELISA. If technology solves social and ethical problems, it will be the most promising in the future.

There are few data about early thermal conditioning (TC) and its effect on later life in rabbits. Therefore, the present study aimed to investigate the impact of exposing two rabbit breeds to early age short-term heat stress (EA-STHS) on physiological parameters and hepatic expression levels of some genes. Rabbits from New Zealand White (NZW) and Baladi Black (BB) rabbit breeds were reared in a controlled environmental chamber (28 ± 2 °C and 40 ± 2% RH). At 42 days of age, rabbits from both breeds were equally divided into two groups; control (untreated) and heat exposed groups (kept at 36 ± 1 °C and 62% RH for 6 h). At 13 weeks of age, rabbits of all groups were re-exposed to acute heat stress (36 ± 1 °C and 62% RH for 6 h). At 13 weeks of age, plasma CORT, plasma MDA, and hepatic MDA had significantly lower levels in the rabbits from the two breeds subjected to EA-STHS than untreated control groups. plasma TAC and the relative hepatic expression of all the studied genes like Hsp70, HspA9, Hsp90α and UCP2 had significantly higher levels in EA-STHS treated NZW and BB rabbits compared with the control groups. In conclusion, the results suggest that EA-STHS has a long-lasting effect on the later life response to acute heat stress in NZW and BB breeds, as indicated by the hepatic expression profile of several genes, corticosterone, and antioxidant parameters. Additionally, each breed had characteristic patterns for the tested parameters at each time point and treatment.

: The feed additives (prebiotics and probiotics) are used to stabilize the healthy gut microbiome by supporting beneficial microorganisms, thereby improving the animal growth rate. Thirty growing lambs, with around 20.50 ± 0.65 kg live weight were placed into five equal groups (6 animals each). The concentrate feed mixture (CFM) + roughage was given to the control groups. The treatments (T) of T1, T2, and T3 treatments were fed the control ration with three levels of prebiotic supplementation: 0.50, 1.00, and 1.50 g/kg CFM of mannan oligosaccharids + beta glucan, respectively. The T4 received the control ration and was supplemented with 1.0 g/kg CFM probiotic (3.0 × 10⁸ CFU/g, Bacillus amyloliquefaciens). The roughage was provided ad libitum, and the animals were supplemented with CFM at 2.00% of the body weight. A digestibility trial was conducted at the end of the 150-day feeding trial. The results demonstrated that increasing the prebiotic to 0.15% enhanced average daily gain and feed efficiency (P < 0.05) when compared to the control group. Although daily gain and feed efficiency in probiotic-fed animals were higher (P < 0.05) than in the control group, they were lower in prebiotic-fed lambs. The blood parameters were within normal range. The animals that received 0.10% prebiotic had the highest economic feed efficiency when compared to the other groups. Prebiotic treatment improved nutrient digestibility and nutritive values; however, the results for control and probiotic treatment were practically identical. Additionally, further research is needed to investigate the effects of prebiotics, probiotics and synbiotics as feed additives on productive and reproductive performance in ruminants.

Background: Using natural compounds as additives in livestock nutrition could be a new goal in livestock production. Milk thistle extract is rich in bioactive compounds such as silymarin, which act as a strong antioxidant agent. Objective: The current study aimed to investigate the metabolic profile, oxidative statue, and immune response after milk thistle extract administration in goats during the peripartum period. Materials and methods: Multiparous pregnant Egyptian Nubian goats (n=16) were allocated into four experimental groups. The first group was kept as the control group. The second group was administrated milk thistle extract (10 g/day), whereas third and fourth groups were administrated 20 and 30 g/day for 4 months, respectively. Blood biochemical parameters were measured using colorimetric and enzyme-linked immunosorbent assay. Gene expressions of antioxidant genes [catalase (CAT), superoxide dismutase (SOD1, SOD2), glutathione peroxidase (GPX1), and peroxiredoxin 2] and transcription factor (nuclear factor erythroid 2 related factor 2) were evaluated using quantitative real-time PCR. Results and conclusion: Biochemical parameters (total protein, glucose, total lipids, total cholesterol, triglycerides, high-density lipoprotein, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, urea, creatinine, triiodothyronine, and thyroxine) in plasma of groups administrated with milk thistle extract did not significantly differ compared with the control group. Milk thistle extract at high levels (20 and 30 g/day) significantly increased the level of activity of antioxidant enzymes (SOD, CAT, and GPX), total antioxidant capacity, and total immunoglobulin in cases compared with the control group. Moreover, milk thistle extract (20 or 30 g/day) significantly decreased the level of malondialdehyde (lipid peroxidation biomarker) and tumor necrosis factor alpha (inflammatory biomarker) in cases compared with the control group. The results indicated a significant increase in transcript abundance of CAT, GPX1, and SOD1 mRNA in the three groups administrated with milk thistle extract compared with the control group. However, mRNA expressions of SOD2, peroxiredoxin 2, and nuclear factor erythroid 2 related factor 2 were significantly up-regulated after administration with milk thistle extract at high levels (20 and 30 g/day). Milk thistle extract exerts antioxidant, anti-inflammatory, and immune-modulator effects during pregnancy and lactation in goat and maintained normal physiological functions.

Identification of molecular characterization of genes underlying livestock productive traits may allow applying advanced biotechnology techniques to improve animal productivity. Growth hormone (GH) controls body growth rate, milk production, reproduction as well as carbohydrate, lipid, and protein metabolism. Therefore, the present study aims to investigate the genetic variations of growth hormone cDNA sequences between Assaf sheep (As_GH) and Boer goat (Bo_GH) that mainly used for genetic improvement in Egypt using bioinformatics analysis. Growth hormone cDNA was isolated from the pituitary gland tissue of Assaf sheep Boer goat and subcloned into pTZ57R/T cloning vector for sequencing. Molecular weight of As_GH cDNA was 665 bp and was 774 bp for Bo_GH cDNA. The complete coding sequences (CDS) of As_GH and Bo_GH were registered in the GenBank database under accession number (AC: MH128986 and AC: MG744290, respectively). High homology percentage was observed (99.5%) between AS_GH and Bo_GH protein sequences with one different amino acid in the As_GH protein sequence (Arg194). The protein sequence of As_GH has only one motif signature; Somatotropin_1 from 79 to 112 aa compared to Bo_GH protein sequences and GenBank database that had two motifs signature. The growth hormone cDNA sequence of Assaf sheep has a unique three single nucleotide polymorphisms (SNPs) (A637A638G639) that encodes for arginine (Arg194); this insertion mutation (AAG) was not found in the growth hormone cDNA sequences of Boer goat in the present study and GenBank database breeds. This mutation can be used to develop SNPs markers for Assaf sheep. GH sequence of Assaf and Boer goat is highly conserved and the homogeny in the codon region (99.5%). The Assaf sheep GH sequence has a unique three SNPs that may be used to develop SNPs markers for such breed. Further studies are needed to investigate the genetic variations of growth hormone gene in different sheep and goat breeds in Egypt and document the relationship between these variations and the productive performance of animals.