Antibacterial, Anti-Biofilm, and Anti-Inflammatory Properties of Gelatin-Chitosan-Moringa-Biopolymer-Based Wound Dressings towards Staphylococcus aureus and Escherichia coli.

In contemporary times, the sustained aspiration of bioengineering and biomedical applications is the progressive advancement of materials characterized by biocompatibility and biodegradability. The investigation of the potential applications of polymers as natural and non-hazardous materials has placed significant emphasis on their physicochemical properties. Thus, this study was designed to investigate the potential of gelatin-chitosan-moringa leaf extract (G-CH-M) as a novel biomaterial for biomedical applications. The wound-dressing G-CH-M biopolymer was synthesized and characterized. The blood haemolysis, anti-inflammatory, antioxidant, and antibacterial activities of the biopolymer were investigated against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial isolates. Our results showed that S. aureus swarming motility was drastically affected. However, the biopolymer had no significant effect on the swarming motility of E. coli. In addition, the biopolymer showed high antibacterial capacities, especially against S. aureus. Plasmid DNA was observed to be effectively protected from oxidative stresses by the biopolymer. Furthermore, the biopolymer exhibited greatly suppressed haemolysis (lower than 2%), notwithstanding the elevated concentration of 50 mg/mL. These results indicated that this novel biopolymer formulation could be further developed for wound care and contamination prevention.

Reformulation of Tunisian Sun-Dried Merguez with Camel Meat: Characterization of Physicochemical and Compositional Changes in Organic Acids, Fatty Acids, Volatile Compounds, and Minerals.

Traditional sun-dried merguez is an authentic Tunisian dried sausage made with a large number of spices and herbs, which was reformulated in this study with camel meat and hump fat and dried as in the artisanal process. This research studied the physicochemical, microbiological, and chemical compositional changes that occurred in fresh camel merguez (FCM) after 12 days of drying to achieve traditional dried camel merguez (DCM). The results showed significant weight loss (54.1%), as well as significant decreases in pH (5.20-4.97), moisture (60.5-12.3%), and water activity (0.986-0.673). These results and the acceptable microbiological quality of DCM can explain the safety of traditionally practiced long-term storage at room temperature. All chemical compositions increased upon drying. The composition of DCM included several organic acids, mainly lactate (2820 mg.kg-1); diverse unsaturated fatty acids, in particular oleic acid (33.2%); and various minerals, specifically iron (8 mg per 100 g), in addition to volatile compounds impacted by herbs and spices rich in terpenes (56.3%). These results can be useful for investing in indigenous products and promoting the exploitation of camel meat.

Study of the Milkability of the Mediterranean Italian Buffalo and the Tunisian Maghrebi Camel According to Parity and Lactation Stage.

While considered as hard milkers, both buffaloes and camels are milked with equipment destined for dairy cows based on external morphological similarities with this species. This work aimed to study similarities and differences in milkability traits between Mediterranean buffaloes and Maghrebi she-camels and to evaluate the effect of parity and lactation stage. A total of 422 milk flow curves recorded with an electronic milkmeter (Lactocorder®) for both species were accessed. Milking characteristics including milk yield per milking, peak milk flow, average milk flow, duration of the main milking phase, duration of total milking, duration of various phases of milk flow, lag time and time to milk ejection, stripping yield, overmilking time and incidence of bimodal milk flow curves were evaluated for both species. Results showed that the values of milk yield per milking, duration of the main milking phase and duration of total milking were higher in buffaloes (3.98 ± 0.10 kg; 4.07 ± 0.11 min; 9.89 ± 0.21 min, respectively) compared to camels (3.51 ± 0.08 kg; 3.05 ± 0.09 min; 3.76 ± 0.09 min, respectively). However, camels had significantly higher peak and average milk flow (2.45 ± 0.07 kg/min and 1.16 ± 0.03 kg/min, respectively). Camels took significantly less time for milk ejection to occur. Only 15.49% of recorded curves were bimodal in buffaloes while 34.93% of bimodal curves were recorded for camels. Overmilking was significantly higher in buffaloes (3.64 ± 0.21 min vs. 0.29 ± 0.02 min). Parity and lactation stage had a significant effect on most studied milking traits suggesting the need for some particular practices with primiparous animals and animals at different levels of lactation for both species.

Development of a bispecific Nanobody anti-F17 fimbria as a potential therapeutic tool.

Pathogenic strains of Escherichia coli F17+ are associated with various intestinal and extra-intestinal pathologies, including diarrhea, and result in significant animal mortality. These infections rely on the expression of virulence factors, such as F17 fimbriae, for adhesion. F17 fimbriae form a protective layer on the surface of E. coli bacteria, consisting of a major structural subunit, F17A, and a minor functional subunit, F17G. Because of the evolution of bacterial resistance, conventional antibiotic treatments have limited efficacy. Therefore, there is a pressing need to develop novel therapeutic tools. In this study, we cloned and produced the F17G protein. We then immunized a camel with the purified F17G protein and constructed a VHH library consisting of 2 × 109 clones. The library was then screened against F17G protein using phage display technology. Through this process, we identified an anti-F17G nanobody that was subsequently linked, via a linker, to an anti-F17A nanobody, resulting in the creation of an effective bispecific nanobody. Comprehensive characterization of this bispecific nanobody demonstrated excellent production, specific binding capacity to both recombinant forms of the two F17 antigens and the E. coli F17+ strain, remarkable stability in camel serum, and superior resistance to pepsin protease. The successful generation of this bispecific nanobody with excellent production, specific binding capacity and stability highlights its potential as a valuable tool for fighting infections caused by pathogenic E. coli F17+ strain.

Improvement of camel milk-clotting: Usefulness of crude extract from green pods of carob (Ceratonia siliqua. L) as a substitute for commercial rennet.

Camel milk transformation into cheese remains an objective to be improved today. This study aimed to improve camel milk clotting using a crude extract from green pods of carob as a substitute for commercial rennet. The composition of the crude carob extract was determined for dry matter and protein content. Milk clotting conditions were studied at different temperatures, pH and CaCl2 concentrations. Milk clotting properties were assessed by milk clotting activity, specific activity and proteolytic activity. Enzymatic hydrolysis of camel milk caseins by crude carob extract and its inhibition were demonstrated by SDS-polyacrylamide gel electrophoresis. Crude carob extract analysis showed a protein and dry matter content of 23.26±0.5 mg/ml and 30.66±0.5 g/l, respectively. Optimal milk clotting activity was observed at 53.6 °C, pH 4.5, and 0.09 M CaCl2. The crude carob extract showed a high milk clotting activity (4.97 U/ml) and a low proteolytic activity (0.04U/ml) with camel milk. The cheese yield of curd produced from camel milk using crude carob extract was the highest (23.95%) compared with that of Camel chymosin (20.5%). The high ratio of milk-clotting to proteolytic activity shows the potential of this extract as a substitute for commercial rennet in the dairy industry.

Inhibitory potential of natural plant extracts against Escherichia coli strain isolated from diarrheic camel calves.

Background: Camel calf's diarrhea is considered the chief economic loss in the camelid population. There is currently no vaccine licensed to prevent colibacillosis in camel calves. The new era of bacterial antibiotic resistance explains the treatment failure and the high mortality and morbidity associated with the disease. Current protective treatments have thus far limited efficacy and need to be replaced. Due to their antimicrobial properties and safety, natural products are recently finding a capital role in infection management. Aims: The current study explores Escherichia coli F17 susceptibility as a clinical strain isolated from diarrheic camel calves to a wide panel of natural products. Methods: Agar diffusion method, integrity of cell membrane, hydrophobicity of bacterial surface, biofilm assays, and motility were used to evaluate the antibacterial activity of Coffea, Retama raetam, Moringa oleifera, Juniperus phoenicea, Uritica dioica, Camellia sinensis, Lavandula angustifolia, and Cuminum cyminum extracts against isolated bacteria. Results: Interestingly, all eight tested extracts have the damaging ability of E. coli F17's cell membrane and cause the nucleic acid release after 12 hours. Escherichia coli F17 strain has the surface of hydrophobicity which changed after contact with extracts of the plant. Moreover, the motility of the studied bacteria changed after exposure to all plant extracts. Conclusion: This study demonstrated that all extracts, exempt U. dioica, can remove up to 50% biofilm of E. coli biomass as compared with the control. Natural extracts can be used as potential antimicrobial agents to mitigate diarrhea in camel calves.

Nanobody-Based Sandwich Immunoassay for Pathogenic Escherichia coli F17 Strain Detection.

Rapid and specific detection of pathogenic bacteria in fecal samples is of critical importance for the diagnosis of neonatal diarrhea in veterinary clinics. Nanobodies are a promising tool for the treatment and diagnosis of infectious diseases due to their unique recognition properties. In this study, we report the design of a nanobody-based magnetofluorescent immunoassay for the sensitive detection of pathogenic Escherichia coli F17-positive strains (E. coli F17). For this, a camel was immunized with purified F17A protein from F17 fimbriae and a nanobody library was constructed by phage display. Two specific anti-F17A nanobodies (Nbs) were selected to design the bioassay. The first one (Nb1) was conjugated to magnetic beads (MBs) to form a complex capable of efficiently capturing the target bacteria. A second horseradish peroxidase (HRP)-conjugated nanobody (Nb4) was used for detection by oxidizing o-phenylenediamine (OPD) to fluorescent 2,3-diaminophenazine (DAP). Our results show that the immunoassay recognizes E. coli F17 with high specificity and sensitivity, with a detection limit of 1.8 CFU/mL in only 90 min. Furthermore, we showed that the immunoassay can be applied to fecal samples without pretreatment and remains stable for at least one month when stored at 4 °C.

Relation between Color and Chemical Composition of Dromedary Camel Colostrum.

Camel milk industrialization faces technological problems related to the presence of colostrum in milk. The determination of color parameters may serve to differentiate between colostrum and milk. This work aimed to study the relationship between the chemical composition of camel colostrum and milk and their colors. Samples of colostrum were collected at 2, 12, 24, 48, 72, 96, 120, 144, 168, and 360 h postpartum (n = 16), and their physicochemical properties (pH, acidity, viscosity, color, dry matter, ash, protein, and fat) were analyzed. The results show that all the components decreased during the first 3 days except fat. The content of this later increased from zero in the three sampling on the first day (2, 12, and 24 h) to 1.92 ± 0.61% at 48 h postpartum. The amount of total dry matter and protein decreased from 20.95 ± 3.63% and 17.43 ± 4.28% to 13.05 ± 0.81% and 3.71 ± 0.46%, respectively, during the first 7 days postpartum. There was a weak correlation between the brightness (L*) of the camel milk and its contents of dry matter, protein, and fat; however, these parameters were strongly correlated with redness (a*) and yellowness (b*). Ash content was poorly correlated with the color parameters. Hence, the measurement of the color parameters of camel colostrum and milk can be a new tool to evaluate their quality.

Effect of heat treatment on the antioxidant activities of camel milk alpha, beta and total caseins.

This study aimed to evaluate the effect of various heating temperatures on the antioxidant activities of camel milk caseins. The samples were processed with three different heat treatments: Pasteurization at low and high temperatures and boiling. Fresh camel milk (unheated) was used as a control. Camel milk caseins were separated by fast ion exchange liquid chromatography (FPLC) and identified by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS page). The antioxidant activities of caseins were measu- red by three different in vitro methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2, 2'-azino-bis (3-ethylbenzthiazoline-6-sulfonate) (ABTS) radical scavenging activity and ferric reducing power assay (FRAP). The antioxidant activity evaluated by the DPPH assay decreased significantly (p<0.05) with the increase in heat treatment of caseins. However, there was no significant difference in ABTS radical scavenging activity and Ferric Reducing Antioxidant Power assay (FRAP) of heat-treated camel caseins compared to unheated onesStill, a decrease was observed in those activities by the increase of temperature in the different casein concentrations. Besides, whatever the concentration tested and the methods applied, the antioxidant activity of beta-casein (ß-CN) was more pronounced than the alpha-casein (α-CN). Therefore, camel milk casein could be used as a natural source of antioxidants which may have a potential application in the food and nutraceutical industries. Throughout the different heat treatments applied, pasteurization at low temperature could be the most suitable alternative to preserve the antioxidant properties of camel milk.

Machine Milkability of Dromedary Camels: Correlation between Udder Morphology and Milk Flow Traits.

This study aims to measure mammary morphological traits with a functional influence on machine milking ability of Tunisian Camels (Camelus dromedarius) and their evolution according to the stage of lactation and parity. Udder and teat measurements were recorded before morning milking and associated with the measurement of milk emission kinetics parameters evaluated with Lactocorder® devices (WMB AG, Balgache, Switzerland) and observations. Three main teat shapes were recorded and their dimensions evolved with parity and stage of lactation. The milk flow curves were classified into three main types according to their maximum and average flow rates and they also evolve according to parity and stage of lactation. An average of 41% of the milk flow curves was bimodal. The correlations showed that some morphological traits were unfavorable to rapid milking and that these increase with parity. Therefore, this study provides the first elements for a morphological selection associated with an aptitude for mechanical milking which appears rather good in our dromedaries. Nevertheless, it will be necessary to monitor a possible negative evolution of the functional and anatomical traits of the udders during the career of the animals.

Oxytocin and cortisol release during suckling, hand-milking and machine milking in camels.

This research paper addresses the hypothesis that oxytocin (OT) could be released during suckling and during milking with and without the presence of a calf and that this release could be regulated by maternal behaviour. Plasma concentration patterns of OT and cortisol (CORT) were measured in six Tunisian dromedary camels during 2 suckling episodes, 2 manual milking episodes with calves beside the mother and 2 machine milking episodes without calves present. Various patterns of OT release were observed between each camel including specific two peak release patterns. Higher plasma OT concentrations were found during the suckling and hand-milking episodes with simultaneous suckling of calves, than during the machine milking episodes without calves. Exclusive mechanical milking episodes also evoked significant mean OT release, although greatly reduced compared to suckling and hand milking. The low basal levels and classical CORT release patterns suggested non-stressful management practices were used and there were very limited differences in udder stimulation between managements. The OT release induced by exclusive suckling and suckling together with hand-milking gives a reference point for what a good milk ejection stimulation is in camels. The important and specific reduction of OT release during machine milking without the calf present could be a physiological consequence of the maternal behaviour (selectivity for the own young) and to a lesser extent explained by a lower stimulation by machine milking.

Genetic Variation in the Prion Protein Gene (PRNP) of Two Tunisian Goat Populations.

Scrapie is a fatal prion disease. It belongs to transmissible spongiform encephalopathies (TSEs), and occurs in sheep and goats. Similarly, to ovine species, the prion protein gene (PRNP) plays a major role in conferring resistance or susceptibility to TSE in goats. This study assesses the variability of PRNP in native and crossed-breed goat populations raised in the Southeast of Tunisia and provides information on the distribution of PRNP haplotypes and genotypes in these goat populations. A total of 116 unrelated goats including 82 native and 34 crossed-breed goats were screened for PRNP polymorphisms using Sanger sequencing. Sequence analysis revealed 10 non-synonymous polymorphisms (G37V, M137I, R139S, I142M, H143R, N146D, R154H, R211Q, Q222K, and S240P), giving rise to 12 haplotypes and 23 genotypes. Moreover, four silent mutations were detected at codons 30, 42, 138, and 179; the former was reported for the first time in goat (nucleotide 60 c→t). Interestingly, the PrP variants associated with resistance (D146 and K222) or with a prolonged incubation time of goat to scrapie (M142, R143, H154, Q211) were absent or detected with low frequencies except for H154 variant, which is present with high frequency (1%, 1%, 4%, 0%, 88%, and 6%, respectively, for native goats, and 0%, 1%, 0%, 1%, 78%, and 1%, respectively, for crossed goats). The analysis of PRNP polymorphisms of goats raised in other regions of the country will be useful in getting a global view of PRNP genetic variability and the feasibility of goat breeding programs in Tunisia.

The experimental infection with a field isolate of the infectious bronchitis virus from eastern Saudi Arabia resulted in seroconversion of the challenged birds with no apparent clinical diseases.

The infectious bronchitis virus (IBV) is still one of the major respiratory viral pathogens of chickens. The IBV infection resulted in a wide range of clinical syndromes in the affected chickens, including respiratory, renal, gonads affections as well as generalized infections. Despite the intensive application of various commercial vaccines against the virus, many outbreaks are still reported in chickens worldwide. Several studies reported the circulation of several strains and genotypes of the IBV in eastern Saudi Arabia. The main goal of the current study was to isolate some of the circulating strains of IBV and assess its ability to reproduce the IBV infections in the challenge birds. Another objective was to monitor the immune status of the infected chickens during the course of this study. To achieve these goals, we used some filed IBV isolates retrieved from an outbreak in a broiler chicken farm in eastern Saudi Arabia in 2014. A total of 220-day-old chickens (110 Ross and 110 native Saudi breed chickens), twenty birds per each group, were used in this study. The chickens in some groups received some IBV vaccines on day one of the experiment, and some are boosted on day 19. All birds were challenged on day 28 of the experiment. Our results showed mild IBV signs in the non-vaccinated control group of chickens; however, the vaccinated chickens did not show any signs of IBV infections. Meanwhile, both the vaccinated and the none- vaccinated birds seroconverted to the IBV as shown by the ELISA results. In conclusion, the response of the IBV infected birds is mainly driven by the vaccination plans they received as a prime-boost regime. Further studies are required for a better understanding of the dynamics of IBV infection in native Saudi chickens.

Effects of two different management systems on hormonal, behavioral, and semen quality in male dromedary camels.

Effects of two different management systems on male dromedary camel hormones, behaviors, and semen parameters were documented. Camels (n=6) were tested under two management systems: (i) housed in single boxes with 1-h freedom (H23); (ii) exposed to females for 17 h (from 3.30 p.m. to 8.30 a.m.) and then housed (ConExF). Blood was collected every morning; camel behavior was recorded twice a day: (i) from 7:00 to 8:00 a.m. to determine the short effects; (ii) from 2:00 to 3:00 p.m. to determine the long effects. Each camel underwent a female parade and semen collection thrice a week; sexual behavior, libido, and semen parameters were assessed. Testosterone and cortisol concentrations were higher in ConExF than H23. Compared to the H23 group, ConExF group spent more time walking, standing tripods, and looking outside their pen/box but they spent less time eating, ruminating, resting, standing, and showing stereotypical behaviors. In the morning, ConExF group spent more time walking, ruminating, and showing typical sexual behaviors compared to themselves during afternoon time and the H23 group. However, in the afternoon time, ConExF camels put more time their heads outside the box through the window and showed higher frequencies of stereotypies, probably due to a higher level of frustration. While the sexual behavioral score was higher and ejaculates showed a higher fraction of milky white and white-colored semen in ConExF than H23 group, their libido was similar. Overall, 17 h of exposure led to an increase in testosterone and cortisol levels, enhancing sexual behavior and semen color, but leading to frustration.

Perspective on therapeutic and diagnostic potential of camel nanobodies for coronavirus disease-19 (COVID-19).

In this paper, we focus on the camelid nanobodies as a revolutionary therapy that can guide efforts to discover new drugs for Coronavirus disease (COVID-19). The small size property makes nanobodies capable of penetrating efficiently into tissues and recognizing cryptic antigens. Strong antigen affinity and stability in the gastrointestinal tract allow them to be used via oral administration. In fact, the use of nanobodies as inhalant can be directly delivered to the target organ, conferring high pulmonary drug concentrations and low systemic drug concentrations and minimal systemic side effects. For that, nanobodies are referred as a class of next-generation antibodies. Nanobodies permit the construction of multivalent formats that may achieve ultra-high neutralization potency and then may prevent mutational escape and can neutralize a wide range of SARS-CoV-2 variants. Due to their distinctive characteristics, nanobodies can be of great use in the development of promising treatment or preventive strategies against SARS-CoV-2 infection. In this review, the state-of-the-art of camel nanobodies design strategies against the virus including SARS-CoV-2 are critically summarized. The application of general nanotechnology was also discussed to mitigate and control emerging SARS-CoV-2 infection.

Characterization and antimicrobial susceptibility of Escherichia coli isolated from healthy farm animals in Tunisia.

Healthy animals can constitute a reservoir for Escherichia coli potentially dangerous for humans. Our objectives were to investigate virulence genes in E. coli isolated from healthy animals in southern Tunisia and to determine their resistance to antimicrobials of high importance in humans and animals. 126 fecal samples were collected from healthy animals (cattle, sheep, goats, chicken, camel, bustard and rabbit) and assayed by PCR for virulence genes and by disk diffusion for antimicrobial resistance. STEC were isolated most frequently from goats (27.7%), sheep (20%) and cattle (14.2%). ExPEC prevalence of iucD (41.6%), papC (27.7%), sfa (13.8%), afa8 (13.8%) and iron (72.2%) was highest in camels. Prevalence of the ExPEC associated genes iss and cnf and the EPEC defining gene eae was highest in rabbits (53.3, 13.3, and 53.3%, respectively). The genes defining enterotoxigenic, enteroinvasive and enteroaggregative E. coli were not detected and faeG was found only in camels (5.5%). The most common phylogenetic groups were B1 (54.5%) and B2 (16.6%). Virulence gene profiles varied greatly between animal species. Overall, antimicrobial resistance was not highly prevalent, the highest resistance being observed against tetracycline, 43.9%.

Vasectomy and Photoperiodic Regimen Modify the Protein Profile, Hormonal Content and Antioxidant Enzymes Activity of Ram Seminal Plasma.

This work aimed to determine the contribution of the testis and epididymis and the effect of the photoperiodic regimen on ram seminal plasma (SP). Semen was collected from 15 mature rams located in an equatorial (Colombian Creole and Romney Marsh, eight intact and two vasectomized) or a temperate climate (Rasa Aragonesa, three intact and two vasectomized). SP proteins were analyzed by Bradford, SDS-PAGE and difference gel electrophoresis (DIGE). Melatonin and testosterone concentrations were quantified by ELISA, and activity of glutathione peroxidase (GPx), glutathione reductase (GRD), and catalase by enzymatic assays. Vasectomy increased protein concentration and the intensity of high molecular weight bands (p < 0.001), with no differences between breeds. DIGE revealed the absence of six proteins in vasectomized rams: angiotensin-converting enzyme, lactotransferrin, phosphoglycerate kinase, sorbitol dehydrogenase, epididymal secretory glutathione peroxidase and epididymal secretory protein E1. Vasectomy also decreased melatonin concentrations in seasonal rams, and testosterone in all of them (p < 0.001), but did not affect antioxidant enzyme activity. Equatorial rams showed lower melatonin and testosterone concentration (p < 0.01) and catalase, but higher GPx activity (p < 0.05). In conclusion, vasectomy modifies the protein profile and hormonal content of ram seminal plasma, whereas the exposure to a constant photoperiod affects hormonal concentration and antioxidant enzymes activity.

Construction of a Nanobodies Phage Display Library From an Escherichia coli Immunized Dromedary.

BACKGROUND: Diarrhea caused by Escherichia coli is a major cause of morbidity and mortality in young animals. Few treatment options are available, mainly antibiotic therapy increasingly limited by resistance to commonly used drugs. OBJECTIVES: The aim of this work was to develop immunotherapy based on the use of camel VHH antibody fragments, or nanobodies, to target pathogenic E. coli surface antigens. MATERIAL AND METHODS: We immunized a camel with a killed strain we had previously isolated from a diarrheic camel calf and identified as expressing the F17 fimbriae antigen. RESULTS: The immunized animal developed an anti-E.coli immune response including heavy-chain antibodies. Lymphocytes from this animal were purified and RNA isolated to create a VHH library by phage display with a size of about 109 individual transformants. Panning on live E. coli cells resulted in the isolation of VHH fragments specific to the cell surface antigens. CONCLUSION: The identification of these antigens can lead to the development of new diagnostic and therapeutic tools against diarrhea.

Factors affecting milk yield and composition of Tunisian camels (Camelus dromedarius) over complete lactation.

This study aimed to investigate the milk production potential and the impact of nongenetic factors on milk yield and composition of Tunisian dromedary camels. Milk recording and sampling were carried out at monthly intervals over complete lactation for 3 years from 95 camels reared in intensive and semi-intensive systems. The overall means of daily milk yield and fat, protein, total solids, and ash contents were 4.21 ± 1.98 l/day, 2.45 ± 0.9%, 2.67 ± 0.74%, 10.75 ± 1.41%, and 0.85 ± 0.08%, respectively. The total milk yield was 1388.41 ± 575.46 l/lactation for 11 months of lactation. The daily milk yield increased regularly throughout lactation until it reached its peak in the 4th month postpartum and then decreased until the 17th month postpartum. The chemical components, except ash, followed an opposite trend to the milk yield. Their minimum contents were recorded during the 7th and 8th months postpartum, while the maximum levels were observed during the 17th month postpartum. Regarding seasonal variation, the highest daily milk yield was recorded during summer (June), whereas the lowest was found in winter (December). In contrast, the maximum and minimum contents of fat and protein were observed during winter (December) and summer (July), respectively. Similarly, total solids content was maximum in January and minimum in August. Parity had no effect on daily milk yield, while all chemical components were higher in milk from primiparous than multiparous camels. Calf sex and management system did not affect the milk yield and composition. These results are useful in order to develop feeding strategies and breeding programs for improving milk production.

Effect of local diets on nutritional and sensory quality of meat of indigenous goats in Tunisian arid regions.

The valorization of natural resources in small ruminants feeding can reduce the cost of feed and produce good meat quality. The objective was to evaluate the effects of local feed resources on the physico-chemical aspects, the sensorial characteristics and the fatty acid profile of goat kid's meat. Twenty-six kids are divided in three groups (average body weight = 15.85 kg; age = 4 months). The groups received oat hay (group control C), dried olive leaves + dried Stipa tenacissima (group OL) or grass hay (group Ko). The animals were slaughtered after 90 days of experience, with an approximate final live weight of 18.5 kg. Total solids, pH, fat, crude protein, vitamin, cholesterol and fatty acid contents of meat were determined. The OL group had the highest ultimate pH (6.82 vs. 6.73); cooking loss, gross composition (total solids, protein and fat), cholesterol and colour coordinates (L, a* and b*) were similar among groups. The vitamin E, affected by diet, was higher in group OL than the other groups (3.71 mg/kg vs. 1.32 and 2.17 mg/kg, respectively, for C and Ko groups). Moreover, meat from this group showed the highest saturated fatty acid. Unsaturated fatty acids content was higher in the meat of C and Ko groups. On the other side, polyunsaturated fatty acid level was not affected by the diet treatment. The n6/n3 ratio was significantly affected by the diet; it was lower in meat of groups Ko and OL (3.17 and 3.38 respectively). The feeding effect on sensory quality of meat was not significant.