Hacina AinBaziz

Seminal plasma biochemistry is a sensitive indicator of sperm responses to cold stress, yet its temporal and breed-specific dynamics in rabbits remain poorly defined. This study investigated temporal changes in key seminal plasma parameters of extended rabbit semen, including total proteins, albumin, cholesterol, triglycerides, aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) during 72 h of storage at 5°C, and their associations with sperm quality traits and oxidative stress biomarkers in New Zealand White (NZW) and Local Algerian Population (LAP) bucks. Eighteen semen pools (nine per breed) were analysed at 0, 4, 24, 48 and 72 h of storage. Distinct breed-specific responses were observed. The LAP bucks showed better resilience, with stable levels of total proteins and albumin, a smaller increase in triglycerides at 48 h (P<0.05) and a delayed significant decline in ASAT activity (48 vs. 4 h in NZW). In NZW, total protein accumulation correlated negatively with sperm quality, albumin and catalase, but positively with superoxide dismutase and glutathione peroxidase activities (P<0.05). In LAP, ASAT activity correlated positively with sperm quality and albumin (P<0.05). Triglycerides emerged as a robust biomarker, showing consistent negative correlations with sperm quality traits in both breeds and with catalase activity when data from both breeds were pooled (P<0.05). Overall, proteins and ASAT acted as breed-specific indicators, whereas triglycerides represented a breed-independent marker of cold storage damage. These findings offer valuable insights for the development of improved semen diluents and could enhance semen analysis protocols during storage.

This study aimed to characterize the reproductive performance of the local Algerian population (LAP) compared with the New Zealand White (NZW) rabbits, by evaluating sexual behavior, semen characteristics, and their modulation by environmental factors, namely photoperiod and temperature-humidity index (THI). Mature bucks (n = 14/breed) were monitored from January to April, with two successive ejaculates collected weekly. Sexual behavior, macroscopic and microscopic semen parameters, and testosterone concentrations were assessed. The effects of breed, ejaculate order, environmental factors, and their interactions were analyzed using Generalized Linear Mixed models. LAP and NZW bucks exhibited similar sexual behavior and blood testosterone levels (p > 0.05). Collection failures and ejaculate rejection causes were mainly clustered within specific individuals rather than being breed-dependent. However, LAP bucks showed higher sperm concentration (p = 0.01), viability (p = 0.02), and membrane integrity (p = 0.04) than NZW bucks, whereas most motility and quantitative semen traits remained comparable between breeds. Increasing photoperiod significantly improved reproductive performance (p < 0.05). Conversely, within the investigated range, THI mainly affected semen collection efficiency through increased urine contamination (p < 0.001), with limited effects on intrinsic sperm quality. Significant breed × environment interactions for sperm concentration (p = 0.03) suggested differential responsiveness between breeds, with LAP bucks showing a stronger positive response to increasing photoperiod and less pronounced variation under THI fluctuations. Overall, LAP bucks exhibited a more favorable seminal profile under the conditions of the present study, supporting the valorization of this local genetic resource for artificial insemination programs under Algerian conditions. Further studies are required to confirm these patterns under summer heat-stress conditions and evaluate their impact on fertility outcomes.

Artificial insemination (AI) in rabbits depends largely on chilled semen storage, but the physiological responses to chilling and associated biochemical changes in seminal plasma (SP) remain poorly understood, particularly across breeds. This study aimed to compare the semen preservation capacity of Algerian local population (LAP) and New Zealand White (NZW) rabbits and to explore the relationship between SP oxidative stress biomarkers and sperm traits during 72 h of chilled storage at 5 °C. Semen pools (nine/breed) were evaluated at 0, 4, 24, 48, and 72 h for motility, viability, and acrosome status. Oxidative stress markers were also assessed in the SP, including malondialdehyde (MDA), reactive oxygen metabolites (ROMs), superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT). LAP sperm showed higher motility (p < 0.001) and viability (p < 0.05), particularly between 4 h and 48 h, and exhibited a lower rate of acrosome reaction (p < 0.001) from 48 h to 72 h. Lower SOD and higher CAT activity in LAP (p < 0.001), correlated with MDA and acrosome status, respectively, may reflect a more balanced antioxidant response. Lipid peroxidation did not appear to be the main factor driving sperm deterioration (p > 0.05). These results demonstrate that LAP rabbits exhibit better resilience to chilled storage compared to NZW and highlight the potential value of CAT and SOD activities as indicators of sperm resilience during chilled storage. Further studies are required to validate and extend these findings, with the aim of improving semen preservation strategies.

Contexte : La biosécurité joue un rôle essentiel dans la prévention et le contrôle de la maladie hémorragique du lapin, qui représente une menace sanitaire et économique majeure pour les élevages de lapins en Algérie. Objectif : Cette étude visait à décrire les pratiques de biosécurité adoptées par les éleveurs de lapins et à identifier les profils de ces derniers. Méthodes : Une enquête a été menée entre janvier 2020 et juin 2022 auprès de 160 éleveurs de lapins répartis dans 28 wilayas du pays. Résultats : Les résultats de l’analyse des correspondances multiples et de la classification ascendante hiérarchique ont permis d’identifier trois profils d’éleveurs sur la base des pratiques de biosécurité déclarées. Le premier groupe (n=70), regroupant 44 % des éleveurs, se caractérisait par un niveau d’application faible des mesures de biosécurité, la majorité des pratiques en conformité y étant sous-représentées. Ce groupe était constitué par des éleveurs possédant des petites unités d’élevage (une à 19 lapines) et ayant moins de 5 ans d’expérience dans l’exercice de la cuniculture. Le deuxième groupe (n=46), comprenant 29 % des éleveurs, regroupait ceux appliquant de manière intermédiaire les mesures de biosécurité. Dans ce groupe, trois pratiques conformes sur neuf étaient sur-représentées. Le troisième groupe (n=44), regroupant 27,5 % des éleveurs, était caractérisé par un bon niveau d’adoption des mesures de biosécurité, avec dix pratiques conformes sur onze sur-représentées. Ce dernier groupe comprenait des éleveurs ayant plus de 5 ans d’expérience dans la pratique de la cuniculture et possédant des grandes unités d’élevage. Conclusions : Cette étude a permis d’établir des profils d’éleveurs appliquant les mesures de biosécurité, mais aussi de mettre en évidence des failles dans les pratiques de biosécurité.

Prickly pear (Opuntia ficus indica L.) could be used in rabbit nutrition in compliance with circular economy principles, global warming issues, and reduction of production costs. This study aims to evaluate the effects of dietary incorporation of prickly pear seed cake (PPSC) on growth, physiological, and histometric parameters in rabbits. A total of 105 rabbits were divided into three experimental groups (n = 35) and fed different diets: a commercial feed (C group), the same feed with alfalfa replaced by PPSC at 10% (10PP group), and at 20% (20PP group). They were group-housed in cages with 5 animals per cage from weaning until slaughtering. While body weights and weight gains were similar in all groups, the coefficients of nutrient digestibility of dry matter, fibers, and ashes, as well as the characteristics of intestinal villi, were improved in the 10PP group compared to the others (p < 0.05). The 20PP group showed a reduction in perirenal and interscapular fat (p < 0.05), as well as lower plasma concentrations of triglycerides and cholesterol compared to the C group (p < 0.001). In conclusion, PPSC can be incorporated into the diets of growing rabbits up to 20% as a partial substitute for alfalfa without the impairment of growth performance. Additionally, the inclusion of PPSC enhanced nutrient digestibility and increased the intestinal absorption surface area.

The aim of the present study was to evaluate the influence of different dietary protein levels on the productive performance of unselected rabbit does and their litters during their first two lactations. For this purpose, fifty-two nulliparous rabbit does, 4.5 months of age and live weight of 3115 ± 71 g, were divided into three groups (17 or 18 females per group), kept in individual cages and each group received only one of the three experimental diets. These diets were iso-energetic (10.8 MJ DE/kg), but with increasing levels of crude protein (CP): 15%, 17% and 19 % for the low (L), medium (M) or high (H) diets, respectively. Breeding was carried out by natural copulation using 6 males of 5-6 months of age and 2865±21 g initial weight, controlled semi-intensive lactation and weaning at 35 days after birth. Female body weight, feed intake, milk production, litter size and weight were monitored at birth and weekly after parturition during the first two lactations. The protein intake of the rabbits increased with the amount of protein in the diet (L vs. M: +12.2%; L vs. H: +18.8%; p < 0.001), without any effect on milk production and feed intake. Milk production was unaffected by parity. Throughout the pre-weaning period, litter size and weight and maternal mortality were unaffected by dietary protein level. Dietary protein level had no effect on live weight, birth to weaning weight gain, milk production or feed intake during the first two consecutive lactations of rabbit does.

In rabbits, ovulation rate is, together with prenatal survival, one of the main limiting factors for litter size. Both components are affected by several factors related to females and their environment. Thus, understanding these components and their factors of variation is key in designing diets, optimisation of reproductive performance and genetic selection. In this review, authors summarise the main components of litter size and their environmental factors of variation. Genetic factors and the main results of genetic selection programmes on components of litter size are also summarised. In this regard, a negative effect of dietary restriction and reduced day light hours is found, as well as a positive effect of body condition, parity order and age of female on ovulation rate. However, an increase in deterioration of oocyte quality has been reported as ovulation rate increases, leading to decreased embryonic and foetal survival. Dietary restriction and heat stress also have a negative effect on embryonic and foetal survival, increasing the failures during gestation while good vascularisation and enough available space in uterine horn are keys to embryonic and foetal survival. Ovulation rate was proposed as indirect selection criterion to improve litter size due to higher heritability. However, this selection was relevant, but it did not modify litter size because of an increase in prenatal mortality. Uterine capacity has been directly related to prenatal survival, although its selection has also been unsuccessful in increasing litter size.

Heat stress is a detrimental factor affecting the welfare of all livestock, especially rabbits, as they are sensitive to high temperatures. The current study investigated the effect of high ambient temperature on growth performance, slaughter traits, physiological indicators, and some hematological and biochemical parameters in Algerian local growing rabbits. A total of 48 local rabbits of both sexes (35 days old) were allotted into two groups (24 per group). The control group rabbits were exposed to an ambient temperature and humidity, averaging 21.8 ± 1.3°C and 51.7 ± 3.6%, respectively. Rabbits in the heat stress group were subjected to a warm ambient temperature and humidity of 30.5 ± 1.82°C and 65.5 ± 7.2%, respectively. The growth performance was measured and calculated from 35 to 91 days of age. Physiological indicators (rectal, skin, and ear temperatures, respiratory, and heart rates) were examined at 88 days of age. The carcass traits, blood metabolites, and hematological parameters of rabbits were measured and calculated at slaughter (92 days of age). The obtained results indicated a decrease in body weight, daily gain, and daily feed intake of rabbits in heat stress rabbits, compared to the control group. However, feed conversion ratio was significantly higher in the heat stress group, compared to the control. Heat stress group rabbits showed significantly higher blood metabolite levels, except the glycemia, which was similar in both groups. No significant effect of heat stress was found on the carcass yield, anterior, posterior, and intermediate parts of the carcass. However, the yield of the other components of the carcass (liver, kidney, peritoneal and inter-scapular fat) was significantly lower in the heat stress group. In the heat stress group, rectal, skin, and ear temperatures as well as heart and respiratory rates, were significantly higher than those of the control group. In the present experimental conditions, exposure of local rabbits to chronic heat stress could induce some changes to biological, physiological, and biochemical parameters leading to altered growth performance.