Queue Fine De Research Articles

Oral supplementation with Scabiosa artropurperea L. aqueous extract improves the invivo sexual behaviour, sperm quality and androgen level in rams.

The effects of an aqueous extract of Scabiosa atropurpurea L. (AES) on the reproduction potential of Queue Fine de l'Ouest rams were evaluated over 9 weeks. Eighteen mature (4-6 years old) rams (52.8 ± 2.6 kg) were divided into three groups. The control (C) group was fed oat hay adlibitum with 700 g of concentrate and the other two groups were fed the same diet supplemented with AES at 1 and 2 mg/kg body weight (AES1 and AES2, respectively). Ram sperm was collected with an artificial vagina (2 × 2 days/week) to evaluate sperm production and quality, antioxidant activity, the adenosine triphosphate (ATP) and calcium concentrations. Sexual behaviour and plasma testosterone concentrations were also investigated. The administration of AES improved sexual behaviour (the duration of contact and the number of lateral approaches). The addition of AES also improved individual spermatozoa motility (C: 71.7% ± 6.3%; AES1: 78.3% ± 4.9%; AES2: 83.8% ± 4.4%), the sperm concentration (C: 5.6 ± 0.36; AES1: 6.4 ± 0.81; AES2: 6.7 ± 0.52 × 109 spermatozoa/mL), the ATP ratio (C: 1 ± 0.08; AES1: 2.1 ± 0.08; AES2: 3.3 ± 0.08) and the calcium concentration (C: 5.6 ± 0.24; AES1: 7.7 ± 0.21; AES2: 8.1 ± 0.24 mmol/L). AES treatment decreased the percentage of abnormal sperm (C: 18.5% ± 1.2%; AES1: 16.2% ± 1.1%; AES2: 14.8% ± 0.94%) and DNA damage (C: 62%; AES1: 27%; AES2: 33%) and was associated with elevated seminal fluid antioxidant activity (C: 22 ± 0.27; AES1: 27.1 ± 1.08 and AES2: 27.5 ± 0.36 mmol Trolox equivalents/L) and plasma testosterone (C: 8.3 ± 0.7; AES1: 11.7 ± 0.4; AES2: 15 ± 0.7 ng/L). In conclusion, our study suggests that S. atropurpurea may be potentially useful to enhance libido and sperm production and quality in ram.

Impact of Body Reserves Dynamic on Productivity and Reproductive Performance in Fat-Tail and Thin-Tail Sheep Breeds over Contrasting Production Cycles.

Under climate change, animal breeding faces severe nutritional challenges, exhibiting their resilience and efficiency to survive and produce. The animals' robustness can be evaluated through the use and reconstitution of body reserves (BR). This study investigated the dynamics of ewes' BR, measured through body weight (BW) and the body condition score (BCS), and their effect on production performances of 480 ewes belonging to fat-tailed Barbarine (BB) and thin-tailed Queue Fine de l'Ouest (QFO) ewes over two consecutive years. The BW and BCS were recorded across physiological stages. Reproductive parameters and lambs' growth were calculated. For both years and breeds, the decrease in the BCS between mating and lambing showed BR mobilization to balance nutritional restrictions, which continues until suckling; after weaning, a BR accretion was noted. The lambs' birth weight was similar regardless of the dams' BCS at lambing, though it was lower in the second year (3.5 vs. 4 kg). Lambs' growth parameters depended on ewes' BCS at lambing and weaning. Fertility rates changed with BCS changes and the higher values (80%) were recorded for ewes with BCSs between 2 and 2.5. However, prolificacy was similar for both breeds and years (p > 0.05). In conclusion, ewes have developed adaptative capacities through BR mobilization to cope with environmental challenges and successfully rear their offspring. To maintain a high offspring growth rate, it is recommended to plan correct flock nutrition during suckling.

Repeated Cross-Sectional Survey of Ectoparasites in Sheep from Central Tunisia: Does Low Prevalence Indicate Good Hygiene or Resistance to Ectoparasites?

Sheep ectoparasites such as chewing lice, fleas and ticks are serious constraints to sheep productivity and are the cause of skin lesions in animals that decrease their market value. This study aims at investigating the ectoparasite fauna infesting small ruminants in the district of Sidi Bouzid (central Tunisia). A total of 1243 Barbarine and Queue Fine de l'Ouest (QFO) sheep were examined every two months for one year. Of the total animals examined, 74 were infested by at least 1 parasite group (5.95%). Three ectoparasite groups were identified as Psoroptes ovis (0.48%; 6/1243), ticks (5.3%; n = 66/1243) and one specimen of Ctenocephalides canis (0.08%; n = 1/1243). The most abundant tick among the 358 specimens was Rhipicephalus sanguineus sensu lato (n = 337; 94.1%), followed by Hyalomma impeltatum (n = 7/358; 1.9%), H. dromedarii (n = 7/358; 1.9%), H. excavatum (n = 5/358; 1.4%) and only two specimens of H. scupense (n = 2/358; 0.55%). The sheep herds showed low infestation prevalence by ectoparasite over the year, with a significant difference according to the seasons (p < 0.05). A higher infestation prevalence was recorded in March (14.36%). Barbarine sheep breed showed significantly higher infestation prevalence (16.8%) compared to QFO (0.8%) (p < 0.01). There were no differences in infestation prevalence according to sex of the animal or age groups. Knowledge of the ectoparasite population harboured by sheep, its activity dynamics and risk factors is required to develop effective ectoparasite control options. The low prevalence of ectoparasite infestation in sheep reported here may be due to possible genetic resistance or simply to successful hygiene measures implemented by farmers.

The effect of increasing extruded linseed level on nutrient digestibility, growth, carcass characteristics, and non-carcass components of lambs from two genotypes.

This research aimed to study the effect of extruded linseed level on digestibility, growth, carcass, and non-carcass components of two genotypes' lambs. For this, 36 lambs, with an average body weight (BW) of 21.3 ± 3.4 for Queue Fine de l'Ouest (QF) and 17.8 ± 2.9kg for the cross QF × D'man (QF × D), were randomly divided into three groups of 12 lambs each (six per genotype) in a 12-week experiment. Sheep in each group received individually oat hay ad libitum and one of three concentrates containing 0% (control), 15% (L15), and 30% (L30) of extruded linseed on a dry matter basis. All concentrates were isocaloric and iso-nitrogenic. In the last 2weeks, digestibility was measured, and then all lambs were slaughtered. The increasing level of extruded linseed did not affect hay and total dry matter (DM) intake as well as nutrient digestibility, except the neutral detergent fiber (NDF) digestibility which was significantly (P < 0.05) reduced by the diet treatment (66.4, 57.8, and 53.0% for C, L15, and L30, respectively). In addition, the different linseed levels resulted in similar average daily gain, final BW, carcass traits, and non-carcass components except the rumen and liver weights which were significantly (P < 0.05) reduced by the increasing linseed level. However, the addition of extruded linseed improved (P < 0.05) the weight of the heart. The carcass tissular composition was not affected by the dietary treatment guarding a similar proportion of muscle, bone, and fat. However, the growth performance and carcass traits were higher for cross QF × D than QF lambs. In addition, the carcasses were leaner (less fat and more muscle) for the cross genotype (P < 0.05) than the pure QF breed. It was concluded that extruded linseed can be used in lamb diet without adverse effects on growth performance and carcass components. Furthermore, the cross could be planned given it resulted in higher growth and better carcass composition.

Substitution effects of soybean meal by Lathyrus sativus L. (grass pea) on nutrient digestibility, growth performances, carcass traits and meat quality of lambs grazing on saline area

Considering the substitution of soybean meal by locally legumes in Mediterranean saline areas, the present work aimed to determine the effect of Lathyrus sativus L. (grass pea) seeds incorporation on digestibility, growth performances, carcass and meat qualities of lambs grazing natural saline rangeland. Forty-five weaned female Queue Fine de l′Ouest lambs (IBW 21.5 ± 2.17 kg) were randomly divided into three groups (n = 15). Each group received 300 g per animal of one of three concentrates containing 0 (Control), 12% (G12) and 30% (G30) of grass pea seeds. All groups were reared on pasture rich on spontaneous halophytic shrubs and herbs for two months. At the end of the experiment, eight lambs per group were slaughtered. Replacing soybean meal by grass pea seeds with the reduction in amount of maize, barley and alfalfa pellet had no effect on nutrient digestibility and feed intake. Digestible crude protein (DCP)/ metabolizable energy (ME) ratio and average daily gain (ADG) were similar among groups (11.15; 183 g/day, respectively). The incorporation of grass pea did not affect (P > 0.05) cold carcass weight and commercial dressing percentage and averaged 13.17 kg and 44.84%, respectively. Red offal percentage was not modified. Moreover, it was found that grass pea seeds did not have any significant effect on carcass fatness (P > 0.05). The average percentage of high-priced joints was 60.87% and was not affected by grass pea seeds incorporation. All lambs had the same shoulder tissue composition. Meat pH, drip and cooking losses were not influenced by diet treatments, as well as the meat chemical composition. Indeed, lamb meat had the same proportions of protein and intramuscular fat. From these findings, it can be concluded that a supply up to 90 g/head/d of grass pea seeds had no effect on digestibility, growth rate, carcass traits and quality of the resultant meat and reduced the use of imported feed ingredients (soybean meal, maize, alfalfa pellet). These results may present significant opportunities for fattening lambs on saline lands.

Substitution of soyabean meal by faba bean improves body weight, sperm production and testosterone concentration in mature Queue Fine de l'Ouest rams.

The current study aimed at investigating the effects of partial or total substitution of soybean meal with faba bean on reproductive parameters of Queue Fine de l'Ouest rams. Eighteen adult rams (49.8 ± 3.7 kg and 2.4 ± 1.5 years old) were divided into three homogenous groups. Rams received oat hay ad libitum and 3 types of concentrate (33 g/BW0.75) where soybean meal was the main protein source (SBM diet, n = 6), partially (50%, SBMFB diet, n = 6) or totally (100% FB diet, n = 6) substituted in nitrogen basis by local faba bean. The volume of ejaculate, sperm concentration and sperm mortality rate were measured weekly by collecting semen using an artificial vagina. Serial blood samples were collected 30 days and 120 days after the beginning of the experiment in order to assess plasma testosterone concentrations. The results showed that hay intake was affected (P < 0.05) by the nature of the nitrogen source incorporated (1032.3 ± 12.2; 1026.8 ± 56.6 and 972.8 ± 39.05 g DM/d for SBM, FB and SBMFB respectively. The average live weight of the rams increased from 49.8 ± 0.4 (week 1) to 57.3 ± 0.9 kg (week 17) without effect of the diet. A positive effect of faba bean incorporation in the concentrate was observed on ejaculate volume, concentration and spermatozoa production. All these parameters were significantly higher in SBMFB and FB groups than in SBM group (P < 0.05). The protein source did not affect the percentage of dead spermatozoa and the total abnormalities which were similar for the three diets (38.7; 35.8 and 38.1% for SBM; SBMFB and FB, respectively). The mean testosterone concentration was higher (P < 0.05) in rams fed with faba bean (1.7 ± 0.7 to 1.9 ± 0.7 ng/ml for the SBMFB and the FB groups respectively) than in rams fed SBM diet (1.06 ± 0.5 ng/ml). It was concluded that the substitution of soybean meal by faba bean improved the reproductive performance and did not affect sperm quality in Queue Fine de l'Ouest rams.

Analysis of MTNR1A Genetic Polymorphisms and Their Association with the Reproductive Performance Parameters in Two Mediterranean Sheep Breeds.

Sheep farming plays an important economic role, and it contributes to the livelihoods of many rural poor in several regions worldwide and particularly in Tunisia. Therefore, the steady improvement of ewes' reproductive performance is a pressing need. The MTNR1A gene has been identified as an important candidate gene that plays a key role in sheep reproduction and its sexual inactivity. It is involved in the control of photoperiod-induced seasonality mediated by melatonin secretion. The aim of this study was to identify SNPs in the MTNR1A gene in two Tunisian breeds, Barbarine (B) and Queue Fine de l'Ouest (QFO). DNA extracted from the blood of 77 adult ewes was sequenced. Selected ewes were exposed to adult fertile rams. A total of 26 SNPs were detected; 15 SNPs in the promoter region and 11 SNPs in the exon II were observed in both (B) and (QFO) breeds. The SNP rs602330706 in exon II is a novel SNP detected for the first time only in the (B) breed. The SNPs rs430181568 and rs40738822721 (SNP18 and SNP20 in our study, respectively) were totally linked in this study and can be considered a single marker. DTL was associated with SNP18 and SNP20 in (B) ewes (p < 0.05); however, no significant difference was detected between the three genotypes (G/G, G/A, and A/A) at these two SNPs. Fertility rate and litter size parameters were not affected by SNP18 and SNP20. There was an association between these two polymorphisms and (B) lambs' birth weights (p < 0.05). Furthermore, the ewes with the A/A genotype gave birth to lambs with a higher weight compared to the other two genotypes for this breed (p < 0.05). There was not an association between SNP 18 and SNP20 and (QFO) ewes' reproductive parameters. These results might be considered in future sheep selection programs for reproductive genetic improvement.

Effect of Saccharomyces cerevisiae Supplementation on Reproductive Performance and Ruminal Digestibility of Queue Fine de l’Ouest Adult Rams Fed a Wheat Straw-Based Diet

This study aimed to investigate the effect of supplementing a wheat straw-based diet with Saccharomyces cerevisiae (S.C.) on feed intake, nutrient digestibility, nitrogen balance, body weight and reproduction performance. The experiment was conducted on 14 Queue Fine de l’Ouest rams between 3 and 4 years of age (body weight (B.W.): 54.7 ± 2.03 kg; body condition score (B.C.S.): 3.5 ± 0.5), for 80 days during the breeding season. The rams were divided into two homogenous groups (n = 7), housed individually in floor pens, and allocated to two dietary treatments. The control group was offered a basal diet of 1 kg/d of wheat straw and 700 g of concentrate. The experimental group (yeast) received the same basal diet supplemented with 10 g of S.C./head/day. The results indicated that the S.C. supplementation had no significant effect on the animal’s body weight, volume and concentration of semen, dry matter intake, crude protein digestibility and nitrogen balance. Compared to the control group, the S.C. addition improved (p &lt; 0.05) the digestibility of dry matter by 7.3%, organic matter by 11.9% and crude fiber by 24%. In addition, the mass motility score increased for the yeast group compared to the control (3.7 ± 0.24 vs. 1.9 ± 0.27, p &lt; 0.05). The total number of dead and abnormal spermatozoa decreased for the yeast group in contrast to the control group (9.28 ± 0.95 vs. 26.8 ± 3.85% and 25.5 ± 3.33 vs. 59.2 ± 2.78%, respectively; p &lt; 0.05). These results showed that adding S.C. to Queue Fine de l’Ouest ram’s diet during breeding season could improve nutrient digestibility and reproductive performance.

Potential use of natural saline pasture for grazing lambs: Effect on digestibility, growth performances, carcass and meat quality

This study aimed to investigate the effects of a natural saline pasture on digestibility, intake, growth, carcass traits and meat quality of lambs. Forty weaned female Queue Fine de l′Ouest lambs (25.4 ± 4.33 kg) were allotted into two groups. The first group raised indoor (I) with oat straw ad libitum and the second grazed natural saline pasture (SP). Both groups were supplemented the same concentrate with 300 and 500 g for SP and I respectively, to have the same average daily gain (ADG). On the 49th day, digestibility and intake were determined on 8 lambs randomly selected from each group, using total fecal collection and Acid Insoluble Ash (AIA) marker method. After 83 days, the 16 lambs were slaughtered at 34 kg. Dry matter (DM), organic matter (OM), crude protein (CP) digestibility and metabolizable energy (ME) were higher (P < 0.001) for SP. Digestible crude protein (DCP)/ME ratio was higher (P < 0.05) for SP group. DM intake (P < 0.05) was lower for SP, while digestible crude protein intake (DCPI) and ME intake (MEI) were similar between the two groups. Water intake was higher for SP (P < 0.001). Final weight and ADG were similar between groups. Carcass dressing and high-priced joints percentages were higher for SP group. Lambs from the SP group had a higher percentage of muscle (P < 0.001) and a lower fat proportion (P < 0.01). No effect of feeding system on carcass linear measurements and on compactness indexes (P >0.05) was noted. Kidney fat decreased in favor of SP group (P < 0.01). There were no differences for fat color, whereas meat of I group had a higher lightness and yellowness than that of SP one. Meat of SP group had a higher DM, protein level (P < 0.05) and lower intramuscular fat (P < 0.01). It has higher content of Fe and Zn (P < 0.01). It could be concluded rearing lambs on saline pasture, with a moderate concentrate supplementation, allowed acceptable growth performances, leaner carcass, and higher nutritional meat quality lambs.

Small ruminants milk from Tunisian oasis: physicochemical characteristics, mineral contents, and microbiological quality.

Characteristics and quality aspects of milk from native ovine Queue Fine de l'Ouest (QFO) and the exotic D'man (DMN) breeds were investigated and compared with those of two subgroups of the local goat population Arbi and Serti. A total of 418 individual milk samples were collected from multiparous lactating animals reared in the continental oasis region of Tunisia. Samples were analyzed for physical parameters (pH, density, and acidity), chemical composition (dry matter, fat, protein, lactose, casein, ash, and casein/protein ratio), mineral concentrations (Ca, P, Na, K, and Ca/P) and microbiological features (total mesophilic aerobic bacteria (TMAB), total coliforms count (TCC), lactic acid bacteria (LAB), sulphite-reducing Clostridium (CSR), yeast and molds (Y/M), Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Salmonella) according to standard methods. The values obtained for physicochemical, mineral, and microbial parameters revealed noticeable differences in the milk of the four studied breeds. On the whole milk samples, the mean value of pH, density, and acidity in milk collected from sheep breeds appeared higher than in milk collected from goat subgroups. As for milk composition, results showed a remarkable disparity between studied breeds and clear superiority of sheep breeds compared to goat's subgroups in all chemical contents being studied (dry matter, fat, protein, lactose, casein, and ash). The differences are more important, especially for dry matter, fat, protein, and casein content, whereas casein/protein ratio distinguished goat's genotypes, and the highest one was obtained for Serti Subgroup. When comparing sheep versus goat's milk for macro-minerals, the current study indicated lower K and higher concentrations of Ca, P, and Na. The milk of QFO sheep, the richest in casein and protein, was expressed with significantly higher levels of calcium and phosphorus compared to the DMN sheep breed and the two goat subgroups. The microbiological examination evidenced that the milk of both species complies with standard criteria required by the Tunisian legislation on the hygiene of milk and dairy products. The microbial quality of ewe milk was higher than goat milk, based on LAB and Y/M, while goats produced milk with better quality referring to TMAB and TCC counts. No significant differences were found for Staphylococcus aureus and Escherichia coli between examined breeds. Got results highlighted the complete absence of the two dangerous pathogens Salmonella and CSR in all investigated samples of small ruminants' milk.

Tick Infestation and Piroplasm Infection in Barbarine and Queue Fine de l'Ouest Autochthonous Sheep Breeds in Tunisia, North Africa.

Simple SummaryTicks and tick-borne pathogens affect the productivity of sheep in Tunisia. Searching for genetically resistant breeds to infestation by ticks may represent an alternative to the overuse of chemical drugs. The aim of this study was to assess if there is any difference in tick infestation among the main sheep breeds in Tunisia. Four hundred and thirty-nine ear-tagged ewes from Barbarine and Queue Fine de l’Ouest (QFO) breeds were examined and sampled each trimester for two years. Ticks were identified to the species level, and piroplasms were detected using Polymerase Chain Reaction (PCR). Queue Fine de L’Ouest ewes were markedly less infested by ticks, and none was infected by piroplasms compared with Barbarine conterparts. The QFO sheep breed could be considered in concrete control strategies, including a breeding program.As ticks and tick-borne pathogens affect the productivity of livestock, searching for genetically resistant breeds to infestation by ticks may represent an alternative to the overuse of chemical drugs. The aim of this study was to assess if there is a difference in tick infestation among the main sheep breeds in Tunisia. The study was carried out between April 2018 and January 2020 in 17 small to middle-sized sheep flocks from 3 regions across Tunisia. Four hundred and thirty-nine ear-tagged ewes from Barbarine (n = 288, 65.6%) and Queue Fine de l’Ouest (QFO) (n = 151, 34.4%) breeds were examined and sampled each trimester. Ticks were identified to the species level, and piroplasms were detected using PCR that targets a common sequence ARNr18S to both Babesia and Theileria genera using catch-all primers. Totally, 707 adult ticks were collected from animals; 91.4% (646/707) of them were Rhipicephalus sanguineus s.l. Queue Fine de l’Ouest animals were markedly less infested by ticks, and no one of them was infected by piroplasms compared to the Barbarine breed. Indeed, during the first four seasons, 21 animals, all from the Barbarine breed, were detected positive for piroplasms. This is the first study in Tunisia about the low susceptibility of QFO ewes to infestation by ticks and to infection by piroplasms. The QFO sheep breed could be raised preferably at high-risk areas of tick occurrence and could be considered in concrete control strategies, including a breeding program.

Genome-wide analyses reveal population structure and identify candidate genes associated with tail fatness in local sheep from a semi-arid area

Under a climate change perspective, the genetic make-up of local livestock breeds showing adaptive traits should be explored and preserved as a priority. We used genotype data from the ovine 50 k Illumina BeadChip for assessing breed autozygosity based on runs of homozygosity (ROH) and fine-scale genetic structure and for detecting genomic regions under selection in 63 Tunisian sheep samples. The average genomic inbreeding coefficients based on ROH were estimated at 0.017, 0.021, and 0.024 for Barbarine (BAR, n = 26), Noire de Thibar (NDT, n = 23), and Queue fine de l'Ouest (QFO, n = 14) breeds, respectively. The genomic relationships among individuals based on identity by state (IBS) distance matrix highlighted a recent introgression of QFO into the BAR and a genetic differentiation of NDT samples, possibly explained by past introgression of European gene pools. Genome-wide scan for ROH across breeds and within the BAR sample set identified an outstanding signal on chromosome 13 (46.58–49.61 Mbp). These results were confirmed using FST index, differentiating fat vs. thin-tailed individuals. Candidate genes under selection pressure (CDS2, PROKR1, and BMP2) were associated to lipid storage and probably preferentially selected in fat-tailed BAR animals. Our findings suggest paying more attention to preserve the genetic integrity and adaptive alleles of local sheep breeds.

Genetic structure of Tunisian sheep breeds as inferred from genome-wide SNP markers

Abstract Assessing the status of genetic variability of native sheep breeds could provide important clues for research and policy makers to devise better strategies for the conservation and management of genetic resources. In this study, a genetic investigation of Tunisian sheep breeds using a genome-wide scan of approximately 50,000 SNPs was performed. To reconstruct genetic structure and relationships among four sheep breeds, 40 samples belonging to fat-tailed Barbarine, Queue Fine de l’Ouest, Noire de Thibar and D’Man breeds were genotyped using Illumina Ovine SNP50 BeadChip. Tunisian breeds averaged 96 % polymorphic loci with an expected heterozygosity (He = 0.36). Genetic analysis of relationship between breeds using Bayesian clustering, MDS and Neighbor-Network analysis, and estimation of FST genetic structure, highlighted the genetic differentiation of Noire de Thibar breed from the other local breeds, reflecting the effect of past events of introgression of European gene pool. The Queue Fine de l’Ouest breed showed a genetic heterogeneity and was close to Barbarine and D'Man breeds, as evidenced by MDS and the lowest level of differentiation with Barbarine breed (FST = 1.8 %). The D'Man breed shared a considerable gene flow with the thin-tailed Queue Fine de l'Ouest breed. Possible factors explaining the genetic patterns observed, such as considerable gene flow probably due to anthropogenic activities in the light of population management and conservation programs.

Effect of treating olive cake with fibrolytic enzymes on feed intake, digestibility and performance in growing lambs

This research evaluated the effects of the addition of a blend of exogenous fibrolytic enzymes composed of a mixture of cellulase and xylanase (CX) to a high-fibre diet on growth performance of meat lambs. The diet contained olive cake (OC), and CX was added to this fibrous by-product at 0 (control, no addition of CX), 4 (CX04) or 16 (CX16) ml of the enzyme preparation per kg OC dry matter. The study was planned according to a quintuplicated 3 × 3 Latin square design, with three experimental treatments (control, CX04, CX16), three 21-day periods (14-day adaptation plus 7-day collection period) and 15 weaned male lambs (Queue Fine de l'Ouest) randomly assigned to the 5 replicates (3 lambs in each replicate). Intake of both dry matter and organic matter were increased (P < 0.05) by 4 % with CX addition. Fibre digestibility was increased (P < 0.05) by 6 % (CX04) and 8 % (CX16) as compared with control. Blood serum biochemistry were not affected (P > 0.05) by CX, except cholesterol concentration that was increased (P < 0.05). As compared with lambs fed the control diet, average daily weight gain was increased (P < 0.05) by 6 and 10 % when lambs were fed CX04 and CX16 diets, respectively. These results indicate that the supplementation of OC-based lamb diets with CX, even at relative low concentrations, improves lamb growth performance as a result of increasing feed intake and enhancing fibre digestibility with no adverse effects on animal health.

GBS Data Identify Pigmentation-Specific Genes of Potential Role in Skin-Photosensitization in Two Tunisian Sheep Breeds.

Simple SummaryMaintaining the flexibility of the genetic resources of native animals to face local environment constraints is still a major challenge. In Tunisia, the Noire de Thibar breed is a local sheep, typically with black coloration, known for its ability to tolerate “hypericum perforatum”, which causes skin photosensitization in white colored sheep. The goal of this study was to perform a genome scan, by considering genotyping-by-sequencing (GBS) markers that were genotyped in divergent coat colored sheep (black vs. white) to identify strong, and recent, artificial selection that is involved in skin-photosensitization. Interestingly, the genomic differentiation analysis identified FST markers within genomic regions containing key pigmentation and photosensitivity related-genes. These findings help in understanding the background of coat color genetics and its potential role in adaptation to local environment constraints.The Tunisian Noire de Thibar sheep breed is a composite breed, recently selected to create animals that are uniformly black in order to avoid skin photosensitization after the ingestion of toxic “hypericum perforatum” weeds, which causes a major economic loss to sheep farmers. We assessed genetic differentiation and estimated marker FST using genotyping-by-sequencing (GBS) data in black (Noire de Thibar) and related white-coated (Queue fine de l’ouest) sheep breeds to identify signals of artificial selection. The results revealed the selection signatures within candidate genes related to coat color, which are assumed to be indirectly involved in the mechanism of photosensitization in sheep. The identified genes could provide important information for molecular breeding.

Reliability of visible reflectance spectroscopy in discriminating between pasture and stall-fed lambs from thin and fat-tailed sheep breeds in dry and hot environment

Considering the additional market value of pasture meat, many authentication methods were developed to discriminate it from meat produced in conventional systems. The visible reflectance spectroscopy technique has proved its efficiency under European conditions and breeds. The present study tested the reliability of this method to discriminate between pasture-fed (P) and stall-fed (S) lambs under North African conditions and investigated the effect of feeding system (FS) (P v. S) and breed (Barbarine; Queue Fine de l’Ouest; and Noire de Thibar) on weight and colour of perirenal, subcutaneous and caudal fat. A total of 18 P and 18 S lambs were used with 6 P and 6 S lambs for each breed. The colour and the reflectance spectrum of different fat tissues were measured. The FS affected weights of all fat tissues and all colour parameters of perirenal and subcutaneous fat (P ≤ 0.01); it almost affected redness and yellowness of caudal fat (P ≤ 0.05; P ≤ 0.01). In all adipose tissues, lightness was higher and both redness and yellowness were lower for S lambs than P lambs. The breed affected weight, lightness and redness of perirenal fat and weight and redness of subcutaneous fat with significant interaction with FS for subcutaneous fat data. To discriminate P lambs from S lambs, the reflectance spectrum of perirenal, subcutaneous and caudal fat at wavelengths between 450 and 510 nm (Method 1, M1) or at wavelengths between 400 and 700 nm using partial least squares discriminative analysis as a classification method (Method 2, M2) were used. M2 yielded to a higher proportion of correctly classified lambs compared with M1 (P = 0.001). The proportion of correctly classified lambs using M2 was 76.4, 75.0 and 80.0% for perirenal, subcutaneous and caudal fat for P lambs and 83.3, 76.4 and 100.0% for S lambs. Despite lower reliability in comparisons to European researches, this study confirmed the efficiency of visible reflectance spectroscopy technique applied on perirenal fat in feeding systems authentication under North African conditions and spotted the caudal fat as a new support for better classification of fat-tailed breeds.

Seasonal variation of lungworm infestation of ewes at Sidi Bouzid slaughterhouse (Central Tunisia)

Respiratory strongyloses are among the most important diseases affecting sheep reared in various farming systems in many countries. In Tunisia, farmers without any scientific background carry out the control of these parasites. A survey was performed in a slaughterhouse in Sidi Bouzid District (Central Tunisia) to assess the prevalence of sheep infestation by lungworms. The study lasted 12 months and involved 720 of the slaughtered ewes. Fecal samples from each ewe were collected and examined by Baermann’s technique. Sixty-eight samples were infested with pulmonary nematode larvae (9.4 ± 2.1%). The population was dominated by Protostrongylus rufescens (4.4 ± 1.5%), followed by Dictyocaulus filaria (2.6 ± 1.2%), Cystocaulus ocreatus and Neostrongylus linearis (1.3 ± 0.8%), and finally Muellerius capillaris (0.3 ± 0.4%), whereas mixed infestations concerned 0.4 ± 0.5% of samples. Lungworm infestation was observed in all age groups with no significant difference (p = 0.64). In addition there was no significant difference in infestation between fat-tailed Barbarine (10.8 ± 3.6%) and Queue fine de l’Ouest (Western Thin Tail) (8.5 ± 2.6%; p = 0.31) sheep breeds. The lowest prevalence was recorded in spring (6.7 ± 3.6%) and the highest in winter (11.7 ± 4.8%), but the difference between seasons was not significant (p = 0.32). This study concerning the activity dynamics of lungworms should be completed by a monitoring project to determine the economic importance of these infestations and provide a solid basis for the establishment of specific control programs against these parasites in Tunisia.

Differences in tick infestation of Tunisian sheep breeds.

Different infestation patterns by ixodid ticks were studied in three sheep breeds in Tunisia: Barbarine, Queue Fine de l'Ouest and their cross-bred animals. During one year, 700 sheep were monitored and examined for tick infestation. A total of 722 ticks were collected from sheep ears. The most frequent tick species was by far Rhipicephalus sanguineus sensu lato (99%) and there were few specimens of Rhipicephalus bursa (1%) (p < 0.001). Overall infestation prevalence was estimated at 10.4%. The lowest infestation prevalence was in Barbarine sheep (7.3%), followed by Queue Fine de l'Ouest (16.7%) and the highest prevalence was in cross-bred sheep (19.1%) (p < 0.001). Mean overall infestation intensity was 1.6 ticks/sheep: lowest in Barbarine (1.4), followed by Queue Fine de l'Ouest (1.7) and cross-bred sheep (1.8). Similarly, abundance was lowest in Barbarine sheep (0.1), and was 0.3 in Queue Fine de l'Ouest and cross-bred animals. The results demonstrated a reduced infestation, possibly due to reduced attractiveness and/or increased resistance to tick infestation, of the Barbarine breed compared with the other two breeds. Further behavioural, genetic and molecular studies are needed to explain the mechanisms for the lower infestation indicators.

The genotoxic and antigenotoxic properties of citrus phenolic limonene on mammalian cell lines

This study aimed to investigate the effects of a natural saline pasture on digestibility, intake, growth, carcass traits and meat quality of lambs. Forty weaned female Queue Fine de l′Ouest lambs (25.4 ± 4.33 kg) were allotted into two groups. The first group raised indoor (I) with oat straw ad libitum and the second grazed natural saline pasture (SP). Both groups were supplemented the same concentrate with 300 and 500 g for SP and I respectively, to have the same average daily gain (ADG). On the 49th day, digestibility and intake were determined on 8 lambs randomly selected from each group, using total fecal collection and Acid Insoluble Ash (AIA) marker method. After 83 days, the 16 lambs were slaughtered at 34 kg. Dry matter (DM), organic matter (OM), crude protein (CP) digestibility and metabolizable energy (ME) were higher (P < 0.001) for SP. Digestible crude protein (DCP)/ME ratio was higher (P < 0.05) for SP group. DM intake (P < 0.05) was lower for SP, while digestible crude protein intake (DCPI) and ME intake (MEI) were similar between the two groups. Water intake was higher for SP (P < 0.001). Final weight and ADG were similar between groups. Carcass dressing and high-priced joints percentages were higher for SP group. Lambs from the SP group had a higher percentage of muscle (P < 0.001) and a lower fat proportion (P < 0.01). No effect of feeding system on carcass linear measurements and on compactness indexes (P > 0.05) was noted. Kidney fat decreased in favor of SP group (P < 0.01). There were no differences for fat color, whereas meat of I group had a higher lightness and yellowness than that of SP one. Meat of SP group had a higher DM, protein level (P < 0.05) and lower intramuscular fat (P < 0.01). It has higher content of Fe and Zn (P < 0.01). It could be concluded rearing lambs on saline pasture, with a moderate concentrate supplementation, allowed acceptable growth performances, leaner carcass, and higher nutritional meat quality lambs.

Meat physicochemical properties, fatty acid profile, lipid oxidation and sensory characteristics from three North African lamb breeds, as influenced by concentrate or pasture finishing diets

This study investigated the meat quality of lambs from three North African breeds (Barbarine, BB; Queue Fine de l’Ouest, QFO; and Noire de Thibar, NT) reared on concentrate (S) or on pasture (P). A total of 18 P and 18 S lambs (20kg initial body weight) were used, with 6 P and 6 S lambs for each breed. After 67 days, all lambs were slaughtered at 26kg final body weight and meat quality was studied. The pH of S lambs 1h post-mortem was lower than that of P lambs (p=0.001). Water cooking loss, colour and sensory quality were not affected by both factors. The pasture and the concentrate meats had the same proportions of lipids and proteins; however QFO and BB breeds had more intramuscular fat than NT breed. The saturated fatty acid proportion was higher for S than P groups (50.63 vs. 44.48%, respectively) and for QFO compared to other breeds. C18:1 was higher for S groups, while C18:2, C18:3 and CLA were higher for P groups. The S group had higher lipid oxidation, while the QFO breed had the highest TBARS. P lambs may have healthier meat than S lambs and the NT breed had the leanest meat with higher concentration of desirable FAs.