Serum metabolomic fingerprints of lambs fed chitosan and its association with performance and meat quality traits

Chitosan (CHI) is a natural biopolymer with antimicrobial, anti-inflammatory, antioxidant and digestive modulatory effects, which can be used in the ruminant diet to replace antibiotics. The aim of this study was to evaluate the effects of CHI on lamb growth traits, nutrients digestibility, muscle and fatty deposition, meat fatty acid (FA) profile, meat quality traits and serum metabolome. Thirty 30-month-old male lambs, half Suffolk and half Dorper, with an average BW of 21.65 ± 0.86 kg, were fed in a feedlot system for a total of 70 days. The lambs were separated into two groups according to the diet: the control (CON) group which received the basal diet and the CHI group which received the basal diet with the addition of CHI as 2 g/kg of DM in the diet. Lambs supplemented with CHI had a greater (P< 0.05) final BW, DM intake, final body metabolic weight (P< 0.05) and lower residual feed intake than the CON group. Animals fed CHI had a greater (P< 0.05) starch digestibility at 14 and 28 days, average daily gain at 14, 42 and 56 days, greater feed efficiency at 28 days and feed conversation at 14 and 42 days in feedlot. Most of the carcass traits were not affected (P> 0.05) by the treatment; however, the CHI supplementation improved (P< 0.05) dressing and longissimus muscle area. The treatments had no effect (P> 0.05) on the meat colour and other quality measurements. Meat from the CHI-fed lambs had a greater concentration (P< 0.05) of oleic-cis-9 acid, linoleic acid, linolenic-trans-6 acid, arachidonic acid and eicosapentaenoic acid. According to the variable importance in projection score, the most important metabolites to differentiate between the CON and the CHI group were hippurate, acetate, hypoxanthine, arginine, malonate, creatine, choline, myo-inositol, 2-oxoglutarate, alanine, glycerol, carnosine, histidine, glutamate and 3-hydroxyisobutyrate. Similarly, fold change (FC) analysis highlighted succinate (FC = 1.53), arginine (FC = 1.51), hippurate (FC = 0.68), myo-inositol (FC = 1.48), hypoxanthine (FC = 1.45), acetate (FC = 0.73) and malonate (FC = 1.35) as metabolites significantly different between groups. In conclusion, the present data showed that CHI changes the muscle metabolism improving muscle mass deposition, the lamb’s performance and carcass dressing. In addition, CHI led to an alteration in the FA metabolism, changes in the meat FA profile and improvements in meat quality.     

Effect of Postweaning Handling Strategies on Welfare and Productive Traits in Lambs

Postweaning management strategies that include an element of social enrichment may reduce weaning stress and improve welfare and productive performance. We analyzed the effect of postweaning handling strategies on welfare and production traits in lambs. After weaning, 36 lambs were assigned to 3 experimental groups with 12 lambs each (control [C], fattening with gentle human female contact [H], and fattening with 2 adult ewes [E]). The average daily gain (ADG) was estimated. Blood samples were taken, and infrared thermography was used to estimate stress variables. There were significant differences among treatments (in favor of alternative strategies) regarding production and stress variables (cortisol, glucose, and creatine kinase). The results suggest that the lambs handled gently during the fattening were less reactive and better able to modulate their physiological stress. The E group adapted better to acute stress than the C group but was less efficient in modulating chronic stress. Both treatments showed higher slaughter live weights and better ADGs compared with the control. The use of social enrichment at weaning, especially to establish a positive human–nonhuman animal bond, alleviates lamb weaning stress and improves welfare and performance.     

The impact of lambing stress on post-parturient behaviour of sheep with consequences on neonatal homeothermy and survival

During lambing the expression of an appropriate behavioural response from both the ewe and the lamb are extremely important to lamb survival. The aim of this study was to show the effect of length and difficulty of the birth process on the expression of maternal and neonatal behaviour with consequences on homeothermy and survival of the neonate lamb. Data were collected from 61 Finnish Landrace × Rahmani crossbred (second generation) primiparous ewes and their single born lambs. Based on the average length of parturition, the ewes were grouped into short birth (less than 32.5 min) and long birth (equal to or higher than 32.5 min) classes. The data recorded include maternal and neonatal behaviour, lamb body temperature over the first 3 days of life and survival rate of the neonate lamb during the first week after birth. Blood samples were also collected from the lamb, pre-suckling and at 24 and 72 h after birth. The obtained sera were assayed for thyroid hormones (T₃ and T₄) that are associated with heat production. Ewes that had prolonged and difficult births did not show competent maternal behaviour compared to mothers with short and un-complicated deliveries, as they were slower to begin grooming their lambs after birth, spent less time licking their lambs, made less low-pitched vocalizations and nosing, were more likely to show rejection behaviour (10.34 % vs 5.4 %, P < 0.05), and were more likely to move away when the lamb sought the udder in an attempt to suck (acceptance rate, 55.5 % vs 64.79 %, P < 0.05). Similarly, lambs from a prolonged and difficult birth were significantly less vigorous after birth, as they had taken more time to stand, reach the udder and to suck successfully. These lambs had lower serum concentrations of T₃ and T₄, and they also had a reduced ability to maintain body temperature after birth. This effect persisted over the first 3 days of life and was associated with higher neonatal mortality in the first week after birth (11.54 %), compared to lambs from short and non-stressful birth processes (2.86 %, P < 0.01). From the present study, it can be concluded that, prolonged deliveries with birthing difficulty were one of the main causes of death of large, single-born lambs, as these complications cause the expression of inappropriate behavioural responses from both the ewe and neonatal lamb. Thus, interventions designed to reduce the incidence of prolonged parturitions are likely to be associated with better welfare for the ewe and the lamb and consequently improved lamb homeothermy and survival.     

Microbiological quality and related factors of sheep milk produced in farms of NE Greece

Sheep herds are a significant capital of dairy industry in Greece, but as dairy farming becomes more complex and intense the need to provide assistance to dairy producers on milk quality is critical. In this study, the quality of raw milk produced in sheep farms of NE Greece was surveyed and the role of various factors was explored. In total, 21 dairy ewe’s farms from the regions of Xanthi and Evros, in the north-eastern Greece were monitored. Milk samples were sampled after the morning milking every 15 days throughout the dairy period (March–June). For the study, a questionnaire was also filled by personal interview with the owners in order to collect information about herd characteristics, health status, handling practices etc. From each farm, air was also sampled for microbiological analysis. Milk samples were examined for chemical components: fat content, protein, lactose, non-fat dry matter (NFDM) and somatic cells count (SCC). Microbiological examination involved the estimation of Total Bacterial Counts (TBC), coliform count (CC), Staphylococcus aureus, Streptococcus sp., and preliminary incubation count (PIC). The possible correlation among different bacterial species and their interaction with SCC and chemical components of milk was also considered. It was examined whether farm management practices could influence the hygiene and the quality of milk. Our results show that as an average TBCs were 5.48 log cfu/ml, SCC: 6.05 log cells/ml, CC: 4.49 log cfu/ml, S. aureus: 3.94 log cfu/ml, Streptococcus sp.: 4.95 log cfu/ml and PIC: 5.7 log cfu/ml. The mean fat, protein, lactose and NFDM were 6.17%, 5.28%, 4.73% and 10.95% respectively. The study revealed significant positive correlation between TBC and PIC (0.825), while SCC was marginally positive correlated with protein and NFDM. No statistically significant correlations observed among SCC with any of the bacterial species. Herd size and farm management practices had considerable influence on SCC and bacterial species.     

Stray voltage threshold is better determined under choice test conditions in sheep

Stray voltage (usually <10 V) can occur in farms. However, very little information is available related to sheep. In addition, little work has been carried out on the effects of the contextual conditions under which the animals are submitted to stray voltage. The aims of this study were (i) to determine the threshold voltage at which lambs start to express avoidance behaviour and (ii) to test if the contextual conditions (i.e. choice v. no-choice conditions) influence the determination of the threshold voltage inducing avoidance behaviour. Six-month-old female lambs fed ad libitum were trained to eat palatable pellets from one or two metallic feeders situated at the end of a 4-m long raceway. Voltage was then applied during a 2-min test to either the only feeder available (no-choice test, 1F, n = 13) or to the first of the two feeders in which the lamb started to eat (choice test, 2F, n = 13). The 1F lambs had to stop eating to avoid the voltage, whereas the 2F lambs were allowed to switch to the non-electrified feeder to carry on eating without any stray voltage. Stray voltage was applied every day, in steps of 0.5 V (AC, 50 Hz), from 0 up to 8 V. For voltages higher than 4.5 V, 2F lambs spent less time eating and ate less in the electrified feeder compared with the non-electrified feeder, and their latency to switch to the non-electrified feeder was shorter. In addition, a transient modification of behaviour was observed at 1.5 V. For 1F lambs, a decrease in the quantity of feed eaten was found for voltages higher than 5 V, although the time spent eating in the electrified feeder was not modified. Finally, 1F lambs urinated more during or just after the 2 min test than 2F lambs for voltages above 5 V. Although lambs with no choice experienced stray voltage as a negative event (increased occurrence of urination), they carried on eating in the electrified feeder whatever the voltage. Therefore, the contextual conditions in which animals are exposed to stray voltage influence their subsequent reactions: the first clear behavioural reaction threshold is easier to detect in choice than in no-choice conditions.     

Nutritional value of fermented olive wastes in growing lamb rations

In an experiment with 40 growing Florina (Pelagonia) lambs, effects of replacing barley grain, sugar beet pulp, and alfalfa meal with fermented olive wastes (FOW) and soybean meal on productivity and meat composition was determined. In the 45-day experiment, lambs were allocated to one of the four treatments of 10 lambs (5 male and 5 female) each. Male and female lambs had an initial body weight (BW) of 19.7 ± 0.8 and 19.5 ± 0.8 kg, respectively, and were individually fed a concentrate mixture ad libitum and alfalfa hay (0.18 kg/lamb/day, dry matter (DM) basis). The FOW was added to the concentrate mixtures at inclusion levels (as fed basis) of 0, 50, 100, and 150 kg/t for treatments FOW0, FOW50, FOW100, and FOW150, respectively. Male lambs grew faster (P<0.01) than female lambs, but no differences (P>0.05) occurred among FOW treatments in final BW, BW gain, DM intake, or feed conversion ratio. Males had heavier (P<0.01) fasted BW and cold carcass weight, and lower (P=0.04) carcass yield than females, but no differences in carcass components among treatments were detected. FOW can be incorporated into concentrates for growing lambs, at levels up to 150 kg/t, with no adverse effects on performance or carcass characteristics.     

Impact of Feeding Saltbush Twigs on Feed Intake,Weight Gain,and Some Mineral Levels of Fattening Awassi Lambs

This experiment was conducted to investigate the effect of the inclusion of saltbush (Atriplex sp.) on the productive performance and blood mineral profile of fattening lambs. Eighteen Awassi lambs, 70 ± 3 days of age and 23 ± 1.8 kg body weights, were randomly selected and divided into three equal groups. Lambs in group one (control) were offered 0.2 kg/day shredded straw of barley (tibin) as the sole source of roughage, while lambs in treatment groups 2 and 3 were provided either 0.2 kg/day Atriplex nummularia or Atriplex halimus as their sole roughage content for 10 weeks. All lambs were also provided 1.1 kg/day of concentrate ration. Although lambs fed A. halimus had significantly (P < 0.05) lower dry matter intake than the control group, the daily weight gain of the two groups of lambs were not significantly different (P > 0.05). Lambs fed either A. nummularia or A. halimus had significantly lower (P < 0.05) calcium and copper levels but significantly higher (P < 0.05) cobalt levels in their blood serum than the control group. Zinc blood serum level was not affected (P > 0.05) by the treatment diets. These results suggested that A. nummularia and A. halimus can substitute for barley straw in the ration of fattening Awassi lambs without compromising lambs weight gain; however, special attention should be given to the mineral status in lambs if saltbush is a major feed component for prolonged periods of time.     

Early pregnancy diagnosis by transrectal ultrasonography in ewes

Two studies were performed to evaluate early pregnancy diagnosis by transrectal ultrasonography (TRUS), using a 7.5-MHz transducer in ewes. In the first study, the objectives were to determine the earliest date that a reliable pregnancy diagnosis could be made (percentage of ewes detected pregnant between days 15 and 20 after mating). In the second study, the objective was to confirm the findings of the first study using a randomized controlled trial. In both studies, the ewes were restrained in dorsal recumbency, using a special chute that maintained the pelvis at an angle of 30–35° lower than the head. In the first study, 30 Suffolk ewes were synchronized and maintained with 2 rams for 5 days. Each ewe was subjected to the first TRUS on day 15 after mating and daily thereafter until day 20 (estrus = day 0). Pregnancy was defined as the presence of an embryo or extra-embryonic membranes. The percentage of ewes detected pregnant at days 15, 16, 17, 18, 19 and 20 were 0% (0/30), 26.7% (8/30), 86% (24/30), 90% (27/30), 96.7% (29/30) and 100% (30/30), respectively (P < 0.001). In the second study, 390 TRUS examinations (TRUS-1) were performed on ewes from 10 to 50 days after mating in a breeding program (group mating, hand mating, cervical and intrauterine AI; breeding group; n = 270) or with vasectomized rams (vasectomized group; n = 120). The breeding date and the status of breeding were unknown to the operator. Thirty of these ewes were mated with vasectomized rams and used repetitively four times as the non-pregnant control group. All females had a subsequent TRUS (TRUS-2) between 7 and 30 days after the TRUS-1 examination. The second TRUS was used as the standard test against which the performance of the TRUS-1 was compared. The percentage of ewes correctly diagnosed at day 15 or less, days 16, 17, 18, and 19 in the breeding group were 0% (0/29), 31.3% (5/16), 40% (8/20), 70% (7/10), and 100% (14/14), respectively (P < 0.001). All the diagnoses of ewes more than 20 days following mating in the breeding group, were correctly predicted (n = 181), as well as all ewes from the vasectomized group (n = 120). It could thus be concluded that the earliest pregnancy diagnosis using a 7.5-MHz transducer by transrectal route based on the presence of positive signs of pregnancy is at day 16 and the maximum sensitivity and negative predictive value was reached at day 20 following breeding.     

日粮中添加不同比例微贮棉秆对湖羊瘤胃微生物区系的影响

【目的】本试验旨在利用16SrDNA高通量测序技术研究不同比例微贮棉秆的添加对断奶湖羊瘤胃微生物区系的影响。【方法】选择日龄相近、体重相似的湖羊30只,根据日粮中微贮棉秆的含量随机分为3组:对照组(S0)、50%微贮棉秆组(S50)和100%微贮棉秆组(S100),每组随机屠宰6只分析生长性能,并取瘤胃液进行瘤胃发酵参数和微生物区系分析。【结果】饲喂50%微贮棉秆能够显著提高湖羊日增重和屠宰率(P0.05)。Bacteroidetes和Firmicutes是湖羊瘤胃的优势菌门,Prevotella和Unclassified Bacteroidales是湖羊瘤胃的优势菌属。日粮中添加100%微贮棉秆可以显著降低湖羊瘤胃菌群的多样性(P0.05);显著降低Unclassified Bacteroidales和BF311的相对丰度(P0.05)。三条代谢通路甜菜素生物合成、吲哚生物碱生物合成和加压素调节水的重吸收随着微贮棉秆比例升高而显著增加(P0.05)。【结论】饲喂50%微贮棉秆在提高日增重的同时对湖羊瘤胃微生物菌群结构与功能影响较小。在生产实践中,微贮秸秆添加量应低于50%。