Effects of suckling duration on growth, slaughtering and carcass quality characteristics of Kivircik lambs

Review of yeast culture concerning the interactions between gut microbiota and young ruminant animals

Microorganisms inhabit the gastrointestinal tract of ruminants and regulate body metabolism by maintaining intestinal health. The state of gastrointestinal health is influenced not only by the macro-level factors of optimal development and the physiological structure integrity but also by the delicate equilibrium between the intestinal flora and immune status at the micro-level. Abrupt weaning in young ruminants causes incomplete development of the intestinal tract resulting in an unstable and unformed microbiota. Abrupt weaning also induced damages to the microecological homeostasis of the intestinal tract, resulting in the intestinal infections and diseases, such as diarrhea. Recently, nutritional and functional yeast culture has been researched to tackle these problems. Herein, we summarized current known interactions between intestinal microorganisms and the body of young ruminants, then we discussed the regulatory effects of using yeast culture as a feed supplement. Yeast culture is a microecological preparation that contains yeast, enriched with yeast metabolites and other nutrient-active components, including β-glucan, mannan, digestive enzymes, amino acids, minerals, vitamins, and some other unknown growth factors. It stimulates the proliferation of intestinal mucosal epithelial cells and the reproduction of intestinal microorganisms by providing special nutrient substrates to support the intestinal function. Additionally, the β-glucan and mannan effectively stimulate intestinal mucosal immunity, promote immune response, activate macrophages, and increase acid phosphatase levels, thereby improving the body's resistance to several disease. The incorporation of yeast culture into young ruminants' diet significantly alleviated the damage caused by weaning stress to the gastrointestinal tract which also acts an effective strategy to promote the balance of intestinal flora, development of intestinal tissue, and establishment of mucosal immune system. Our review provides a theoretical basis for the application of yeast culture in the diet of young ruminants.

Carcass Characteristics and Meat Quality of Karacabey Merino lambs Reared under Triticale and Oat Pastures Compared with Stall-Fed Lambs

Fifty-eight Karacabey Merino lambs were used to study the effects of feeding system (triticale pasture, oat pasture, or stall-fed), birth type (single or multiple), gender (male or female), and birth year (2016 or 2017) on various carcass and meat quality characteristics. Stall lambs had higher conformation (CS) and fatness (FS) scores, and higher meat L* and h* values than the two pasture groups, possibly due to higher fat content, while oat pasture lambs had the most tender meat. Single-born lambs had higher CS, FS, and Longissimus thoracis muscle section area, while females had higher subcutaneous and non-carcass fat deposits than their counterparts. Both single-born lambs and 2016-born lambs had higher meat a* and C* values than their counterparts. In conclusion, a pasture-based feeding system is more suitable for Karacabey Merino lambs than a stall feeding system, if lean meat and/or meat products are preferred. However, it should not be ignored that stall-fed lambs showed a better fattening performance in terms of conformation and fatness, during the same period.

Effects of milk replacer feeding level on growth performance, rumen development and the ruminal bacterial community in lambs

Feeding with a suitable level of milk replacer (MR) can improve the survival rate and stimulate the growth potential of early lambs. However, feeding excessive MR might be detrimental to rumen development and microbial colonization. Herein, we investigated the effects of feeding different levels of MR on rumen digestive function and ruminal microorganisms. Fourteen healthy male Hu lambs with similar birth weights and detailed pedigree records were divided into two groups to receive low (2% of average body weight per day) and high (4% of average body weight per day) levels of MR. We analyzed the effects of the MR feeding level on growth performance, fiber degradation rates, rumen fermentation parameters, enzyme activities and rumen histomorphology. We found that feeding with a high level of MR improved the average daily gain of early lambs, but decreased the starter intake, rumen weight and papillae length. We also analyzed the effects of the MR feeding level on the rumen microbiota using 16S-rRNA amplicon sequencing data. The results showed that high a MR feeding level increased the rumen microbial diversity but decreased the abundance of many carbohydrate degrading bacteria. Several bacterial genera with significant differences correlated positively with rumen cellulase activity and the acid detergent fiber degradation rate. Our results suggested that a high level of MR could improve the growth performance of early lambs in the short term; however, in the long term, it would be detrimental to rumen development and have adverse effects on the adaptation process of the microbiota to solid feed.

Effects of Dietary Supplementation with Glycerol Monolaurate (GML) or the Combination of GML and Tributyrin on Growth Performance and Rumen Microbiome of Weaned Lambs

Our objective was to evaluate the effects of dietary supplementation with glycerol monolaurate (GML) or the combination (Solider, SOL) of GML and tributyrin (TB) on the growth performance and rumen microbiome of weaned lambs. Thirty-six male Hu lambs (11.46 ± 0.88 kg BW and 40 ± 5 days of age) were divided into three treatment groups: (1) CON: basal diet, (2) GML: basal diet supplemented with GML at 1.84 g/kg DM, and (3) SOL: basal diet supplemented with SOL at 3 g/kg DM. GML increased the final BW (p = 0.04) and ADG (p = 0.02) compared with CON. There were no significant differences in the DMI (p > 0.10) among the three treatment groups. GML and SOL tended to decrease the dry matter intake/average daily gain (p = 0.07) compared with CON. GML tended to increase the apparent digestibility of CP (p = 0.08) compared with CON. SOL increased the apparent digestibility of NDF (p = 0.04) compared with CON. The Chao1 and Shannon indexes of SOL were both significantly higher than those of the other groups (p = 0.01). LefSE analysis showed that Bifidobacteriaceae of the Bifidobacteriales was enriched in the GML group. In addition, compared with GML, SOL reduced the relative abundance of Actinobacteria (p < 0.01) and increased the relative abundance of Verrucomicrobia (p = 0.05), and GML reduced the relative abundance of Ruminococcus (p = 0.03). Our results indicated that dietary supplementation with GML or SOL improved growth performance and feed conversion, and changed the rumen microbiome of weaned lambs.

Carcass and Meat Quality of Lambs from Thin-Tailed and Fat-Tailed Breeds at Five Different Slaughter Weights

In lamb production, deciding the optimal slaughter weight (SW) has great importance on product quality. The aim of the study was to determine the optimum SW for lambs from a thin-tailed breed (Kivircik) and a fat-tailed breed (Kangal Akkaraman) in order to get high-quality meat and carcass. Kivircik (n=60) and Kangal Akkaraman (n=59) lambs were allotted to five SW groups (20, 28, 36, 44 and 52 kg). In Kivircik lambs, backfat thickness and fatness score gradually increased in parallel with the increase in SW, while the increase in the tail fat and kidney knob and channel fat (KKCF) proportions were observed by up to 36 kg. In Kangal Akkaraman lambs, evident increases in fatness parameters, except tail fat proportion, were observed when the SW increased from 44 kg to 52 kg. Meat pH, Warner Bratzler shear force (WBSF) and cooking loss values were not influenced by SW in lambs of both breeds. As SW increased in Kivircik lambs, there was a significant decrease in meat lightness and an increase in yellowness. In Kangal Akkaraman breed, lambs slaughtered at 20 kg and 28 kg had higher L* values, and lower a* and C* values than those of other SW groups. In Kivircik lambs, the total PUFA proportion and the ΣPUFA/ ΣSFA ratio were lower in SW-44 and SW-52 groups than those of SW-20 and SW-28 groups. Decreases of these parameters were in SW-52 group in Kangal Akkaraman lambs. In meat samples of both breeds, SW-52 groups had a lower Σn-3 proportion and a higher Σn-6 / Σn-3 ratio than other SW groups. In Kivircik lambs, the panellists evaluated the meat of SW-20 and SW-28 groups as tender compared to those in SW-44 and SW-52 groups. In Kangal Akkaraman breed, flavour intensity in the meat of SW-52 lambs was higher than those of SW-20 and SW-28 groups. Results of the study indicate that slaughtering of lambs at 20 kg and 28 kg in both breeds provided better meat quality but caused lower carcass weight. Therefore, slaughtering Kivircik and Kangal Akkaraman lambs at 20 kg and 28 kg live weight might be recommended especially to farmers, who aim to obtain high-quality lamb meat. In this case, it should not be ignored that the amount of meat produced will be less. On the other hand, slaughtering lambs at about 44 kg weight could be recommended to farmers, who aimed to obtain as much quality lamb carcasses as possible without any negative influence on meat quality.

Developmental changes of nutrient digestion in young lambs are influenced by weaning and associated with intestinal microbiota

Understanding the effects of weaning on the changes of digestive function could help to design efficient intervention strategies for promoting the development of the lamb during the early stages of life. In this study, 24 lambs were divided into two groups (control group, lambs were not weaned; and weaning group, lambs were weaned at 21 days of age). The growth, nutrient digestion, gastrointestinal enzyme activity, plasma biochemical indicators, and intestinal microbiota at 7-49 days were determined, as well as the impact of early weaning. The nutrient digestion changed rapidly with age, especially at 14-28 days (p < 0.05). Weaning reduced the dry matter (DM), crude protein (CP), and ether extract (EE) intake and digestion, but increased the starch, neutral detergent fiber (NDF), and acid detergent fiber (ADF) intake and digestion (p < 0.05). Weaning did not affect the overall jejunal microbiota (p > 0.05), but affected the relative abundance of certain bacteria taxa (p < 0.05). Lactic acid-producing bacteria, such as Olsenella, Bacillus, Sharpea, and Bifidobacterium are closely related to CP or EE digestion and growth performance (p < 0.05). In summary, we delineated the pattern of nutrient digestion and intestinal microbiota development in young lambs, and the impact of early weaning.

Review: Factors affecting sheep carcass and meat quality attributes

Sheep meat comes from a wide variety of farming systems utilising outdoor extensive to indoor intensive with animals of various ages at slaughter. In Europe, slaughter may occur from 4 weeks of age in suckling light lambs to adult ages. More than any other animal species used for meat production, there are strong country-specific preferences for sheep meat quality linked to production system characteristics such as dairy or grassland-based systems. This article critically reviews the current state of knowledge on factors affecting sheep carcass and meat quality. Quality has been broken down into six core attributes: commercial, organoleptic, nutritional, technological, safety and image, the latter covering aspects of ethics, culture and environment associated with the way the meat is produced and its origin, which are particularly valued in the many quality labels in Europe. The quality of meat is built but can also deteriorate along the continuum from the conception of the animal to the consumer. Our review pinpoints critical periods, such as the gestation and the preslaughter and slaughter periods, and key factors, such as the animal diet, via its direct effect on the fatty acid profile, the antioxidant and volatile content, and indirect effects mediated via the age of the animal. It also pinpoints methodological difficulties in predicting organoleptic attributes, particularly odour and flavour. Potential antagonisms between different dimensions of quality are highlighted. For example, pasture-feeding has positive effects on the image and nutritional attributes (through its effect on the fatty acid profile of meat lipids), but it increases the risk of off-odours and off-flavours for sensitive consumersand the variability in meat quality linked to variability of animal age at slaughter. The orientation towards more agro-ecological, low-input farming systems may therefore present benefits for the image and nutritional properties of the meat, but also risks for the commercial (insufficient carcass fatness, feed deficiencies at key periods of the production cycle, irregularity in supply), organoleptic (stronger flavour and darker colour of the meat) and variability of sheep carcass and meat quality. Furthermore, the genetic selection for lean meat yield has been effective in producing carcasses that yield more meat, but at a penalty to the intramuscular fat content and eating quality of the meat, and making it more difficult to finish lambs on grass. Various tools to assess and predict quality are in development to better consider the various dimensions of quality in consumer information, payment to farmers and genetic selection.

Evaluation of the functionality of EUROP carcass classification system in thin-tailed and fat-tailed lambs

Aim of study was to investigate the relationship of EUROP carcass fatness and conformation classes with carcass and meat quality characteristics in thin-tailed (Kivircik) and a fat-tailed (Kangal Akkaraman) lambs. A total of 96 lamb carcasses (48 Kivircik and 48 Kangal Akkaraman breed) were examined. Distribution of carcasses in conformation and fatness classes were more limited in Kangal Akkaraman carcasses. More accurate predictions were obtained in Kivircik lambs compared to Kangal Akkaraman lambs in terms of backfat thickness, kidney knob and channel fat percentage, longissimus thoracis muscle area, weights of high-value carcass joints, weights of tissues in the hind limb and muscle/bone ratio. EUROP classification system was not appropriate for predicting meat quality in thin-tailed and fat-tailed lambs. The combination of EUROP fatness and conformation classes with cold carcass weight can be used to predict weights of high-value carcass joints and weights of hind limb tissues.

Ages of weaning influence the gut microbiota diversity and function in Chongming white goats

To study the effect of weaning age on the gut microbiota diversity in the lambs of Chongming white goats, fresh feces from the lambs weaned at 30, 45, and 60 days of age were collected 3 days after weaning at 33, 48, and 63 days of age, for microbial composition analysis by 16S rRNA sequencing. The serum concentrations of lipid metabolites were also investigated at the fecal collection dates. Serum and feces from the ewe-reared groups at 33, 48, and 63 days of age were used as controls. The alpha diversity increased significantly after weaning and with the aging of the lambs. Levels of Ruminococcaceae, Lachnospiraceae, and Ruminococcus varied significantly according to the weaning treatment in lambs (P < 0.05). Butyrate-producing gut bacteria such as Ruminococcaceae_UCG-010, Ruminococcaceae_UCG-013, Ruminococcaceae_UCG-014, Ruminococcaceae_UCG-005, Ruminococcaceae_UCG-002, Lachnospiraceae_AC2044_group, and Lachnospiraceae_NK4B4 were identified as significantly increased genera (P < 0.05) in the feces of weaned Chongming white lambs. Additionally, the abundance of fiber degradation-associated bacteria including Ruminococcaceae_UCG-005, Ruminococcus_1, and Ruminococcus_2 significantly increased with lamb weaning age (P < 0.05). Correlation analysis showed that Lachnospiraceae_AC2044_group, norank_f__Bacteroidales_S24-7_group, and Ruminococcaceae_UCG_005 were negatively correlated, and Lachnoclostridium was positively correlated with levels of cholesterol, while Blautia showed positive correlation with low-density lipoprotein cholesterol in serum samples from weaned lambs. This study helped to understand the maturing development of gut microbiota in Chongming white goats under weaning stress. KEY POINTS: • Effects of weaning age on the gut microbiota diversity in Chongming white goat lambs were studied. • Some butyrate-producing gut bacteria were significantly increased after weaned. • Correlations of gut microbiota and lipid metabolites were analyzed.

Growth, Carcass and Meat Characteristics of Grass-Fed Lambs Weaned from Extensive Rangeland and Grazed on Permanent Pastures or Alfalfa

Western Patagonia lamb production systems are based on extensive rangeland. The harsh climate limits the adoption of more intensive systems. Therefore, producers must focus on developing differentiated products. The aim of this study was to evaluate growth patterns, carcasses and nutritive value of meat from 45 lambs. Lambs were divided into three groups: 15 lambs were slaughtered at weaning (W), with the remaining 30 weaned lambs being allocated to grazing either alfalfa (AG) or permanent pasture (PPG). AG lambs were significantly heavier and had higher condition scores than PPG lambs. Further, AG lambs showed higher carcass weight and larger tissue depth and commercial cuts. Moreover, W lambs had lower shear force and more tender meat than either AG or PPG lambs. The three systems showed a low shear force and acceptable sensory traits. Low levels of cholesterol, with low levels of saturated fat, classified these cuts of meat as extra lean. W lambs had higher omega-3 fatty acid content than AG or PPG lambs. Overall, results showed that meat from the three lamb production systems showed health claimable levels of omega-3 fatty acids and were low in fat and thereby, can be classified as lean meat.

Rumen fluid transplantation affects growth performance of weaned lambs by altering gastrointestinal microbiota, immune function and feed digestibility

Although rumen fluid transplantation (RT) has been developed to confer benefits for adult ruminants by altering gastrointestinal tract microbiota, the question remains whether RT can also benefit weaned lambs. Hence, in this study, thirty-eight pre-weaning lambs were randomly assigned to one of three treatment groups: control lambs (CON) received 25 ml of normal saline solution, and lambs in two RT groups received 25 ml of rumen fluid either from 3-month-old lambs (LT) or from one-year-old adult ewes (AT). The effects on their growth performance, nutrient digestibility, some blood parameters and gastrointestinal tract microbiota were monitored. There were differences (P < 0.05) in rumen bacterial composition between the groups at weaning, at 3 months and at 1 year. Rumen fluid transplantation decreased (P < 0.05) average daily feed intake, average daily gain in live weight and apparent digestibility of ether extract in the LT group, and it decreased (P < 0.05) apparent digestibility of NDF and ADF in the AT group. Rumen fluid transplantation also increased (P < 0.05) concentrations of serum immunoglobulin A in the AT group and increased (P < 0.05) serum concentrations of interleukin-6, interferon alpha and D-lactate in both LT and AT groups. Bacterial α-diversity in the rumen and rectum was not affected by RT (P > 0.05), but a bacterial community change was observed after RT, and the abundance of some dominant bacteria in both rumen and rectum changed after RT (P < 0.05). Analysis of correlations between the parameters indicated that the altered gastrointestinal microbiota and accelerated maturity of rumen microorganisms induced by RT caused some impairment of gastrointestinal integrity and immunity, which led to decreased feed intake, reduced feed digestibility and lower growth performance of the weaned lambs. In conclusion, rumen fluid transplantation altered the gastrointestinal microbiota causing adverse effects on feed intake, feed digestibility and growth performance of the weaned lambs.

Does early weaning shape future endocrine and metabolic disorders? Lessons from animal models

Obesity and its complications occur at alarming rates worldwide. Epidemiological data have associated perinatal conditions, such as malnutrition, with the development of some disorders, such as obesity, dyslipidemia, diabetes, and cardiovascular diseases, in childhood and adulthood. Exclusive breastfeeding has been associated with protection against long-term chronic diseases. However, in humans, the interruption of breastfeeding before the recommended period of 6 months is a common practice and can increase the risk of several metabolic disturbances. Nutritional and environmental changes within a critical window of development, such as pregnancy and breastfeeding, can induce permanent changes in metabolism through epigenetic mechanisms, leading to diseases later in life via a phenomenon known as programming or developmental plasticity. However, little is known regarding the underlying mechanisms by which precocious weaning can result in adipose tissue dysfunction and endocrine profile alterations. Here, the authors give a comprehensive report of the different animal models of early weaning and programming that can result in the development of metabolic syndrome. In rats, for example, pharmacological and nonpharmacological early weaning models are associated with the development of overweight and visceral fat accumulation, leptin and insulin resistance, and neuroendocrine and hepatic changes in adult progeny. Sex-related differences seem to influence this phenotype. Therefore, precocious weaning seems to be obesogenic for offspring. A better understanding of this condition seems essential to reducing the risk for diseases. Additionally, this knowledge can generate new insights into therapeutic strategies for obesity management, improving health outcomes.

Effect of Early Weaning on the Intestinal Microbiota and Expression of Genes Related to Barrier Function in Lambs

Weaning stress has been reported to impair intestinal health. The gut microbiota plays a vital role in the long-term health of the host. However, our understanding of weaning stress on gut microbiota and barrier function is very limited in livestock species, especially lambs. We investigated the effects of early weaning stress on intestinal bacterial communities and intestinal barrier function in lambs. A total of 24 neonatal male Hu lambs were randomly allocated into two groups, one weaned on day 28 and the other weaned on day 56. At 42 and 84 days, six lambs from each group were randomly selected and sacrificed. Ileal tissue and ileal digesta were collected to compare the differences in ileal microbiota and the mRNA levels of Toll-like receptors (TLRs) and tight junction proteins between the early weaning group and the control group at day 42 when the early weaning group have been weaned for 14 days, and at day 84 when the 28 and 56 days weaning groups had been weaned for 56 and 28 days, respectively. 16S rRNA gene sequencing of ileal samples revealed that the ileal microbiota was very different between the two groups, even at 84 days of age. Early weaning significantly increased alpha diversity and altered the relative abundance of several bacterial taxa. The expression of genes related to intestinal barrier function was affected by early weaning. Early weaning significantly increased ileal mRNA levels of TLR1 on days 42 and 84; TLR2, TLR4, and TLR5 on day 84; claudin1 and claudin4 on day 42; and occludin on day 84. We demonstrate that early weaning not only altered the ileal microbiota on day 42 (compared with lambs that were not weaned), but also had lasting effects on the ileal microbiota at day 84; furthermore, early weaning impacts expression levels of genes related to intestinal barrier function.