Effects of dietary supplementation with rosemary oil on methanogenic bacteria density, blood and rumen parameters and meat quality of fattening lambs

Potential of Organic Acids, Essential Oils and Their Blends in Pig Diets as Alternatives to Antibiotic Growth Promoters

Over the years, the use of management and feeding strategies to enhance pig productivity while minimizing the use of antibiotic growth promoters has grown. Antibiotic growth promoters have been widely used as feed additives to reduce diet-related stress and improve pig performance. However, increasing concern about the consequences of long-term and increased use of antibiotic growth promoters in animal production has led to a paradigm shift towards the use of natural organic alternatives such as plant essential oils and organic acids in pig nutrition to enhance growth. Antibiotic growth promoters endanger human health by allowing multidrug-resistant genes to be transferred horizontally from non-pathogenic to pathogenic bacteria, as well as directly between animals and humans. Scientific research shows that alternative growth promoters such as essential oils and organic acids appear to improve pigs' ability to prevent pathogenic bacteria from colonizing the intestinal system, stabilizing the gut microflora and promoting eubiosis, as well as improving immunity and antioxidant stability. The purpose of this review was to provide an in-depth review of organic acids and essential oils as growth promoters in pig production, as well as their effects on productivity and meat quality. Organic acids and essential oils in pig diets are a safe way to improve pig performance and welfare while producing antibiotic-free pork.

In Vitro Fermentation and Degradation Characteristics of Rosemary Extract in Total Mixed Ration of Lactating Dairy Cows

Rosemary extract (RE) is characterized as an antioxidant, and it has the potential to reduce methane emission and change microbial fermentation. Hence, to the extent of the evaluation of RE in ruminant nutrition, the in vitro fermentation technique was used to investigate the effects of RE on the fermentation characteristics of a total mixed ration (TMR) fed to dairy cows. Different doses of RE were added to the TMR to obtain different concentrations of antioxidants, including 0 (CON), 0.05 (LRE), and 0.10 g/kg (HRE). A total of 500 mg ground TMR was incubated in buffer solution and rumen fluid for 48 h at 39 °C. Nutrient degradability, gas production parameters, gas composition, fermentation parameters, and microbial composition were analyzed. The results showed that nutrient degradability and total volatile fatty acid concentration were not affected by the treatments. Furthermore, total methane production and proportion were depressed in a dose-dependent way. The RE increased the propionate concentration and proportion linearly and decreased the acetate concentration and proportion linearly. Finally, microbial diversity analysis showed that the richness and evenness indexes were unchanged by different treatments, while Prevotella_1 was decreased and Prevotella_7 was increased with RE supplementation. In conclusion, RE is an effective inhibitor of methane emission of microbial fermentation and changed the profile of volatile fatty acids with no disadvantageous effects on diet utilization.

Essential Oils as a Dietary Additive for Small Ruminants: A Meta-Analysis on Performance, Rumen Parameters, Serum Metabolites, and Product Quality

There is an increasing pressure to identify natural feed additives that improve the productivity and health of livestock, without affecting the quality of derived products. The objective of this study was to evaluate the effects of dietary supplementation with essential oils (EOs) on productive performance, rumen parameters, serum metabolites, and quality of products (meat and milk) derived from small ruminants by means of a meta-analysis. Seventy-four peer-reviewed publications were included in the data set. Weighted mean differences (WMD) between the EOs treatments and the control treatment were used to assess the magnitude of effect. Dietary inclusion of EOs increased (p < 0.05) dry matter intake (WMD = 0.021 kg/d), dry matter digestibility (WMD = 14.11 g/kg of DM), daily weight gain (WMD = 0.008 kg/d), and feed conversion ratio (WMD = −0.111). The inclusion of EOs in small ruminants’ diets decreased (p < 0.05) ruminal ammonia nitrogen concentration (WMD = −0.310 mg/dL), total protozoa (WMD = −1.426 × 105/mL), methanogens (WMD = −0.60 × 107/mL), and enteric methane emissions (WMD = −3.93 L/d) and increased ruminal propionate concentration (WMD = 0.726 mol/100 mol, p < 0.001). The serum urea concentration was lower (WMD = −0.688 mg/dL; p = 0.009), but serum catalase (WMD = 0.204 ng/mL), superoxide dismutase (WMD = 0.037 ng/mL), and total antioxidant capacity (WMD = 0.749 U/mL) were higher (p < 0.05) in response to EOs supplementation. In meat, EOs supplementation decreased (p < 0.05) the cooking loss (WMD = −0.617 g/100 g), malondialdehyde content (WMD = −0.029 mg/kg of meat), yellowness (WMD = −0.316), and total viable bacterial count (WMD = −0.780 CFU/g of meat). There was higher (p < 0.05) milk production (WMD = 0.113 kg/d), feed efficiency (WMD = 0.039 kg/kg), protein (WMD = 0.059 g/100 g), and lactose content in the milk (WMD = 0.100 g/100 g), as well as lower somatic cell counts in milk (WMD = −0.910 × 103 cells/mL) in response to EOs supplementation. In conclusion, dietary supplementation with EOs improves productive performance as well as meat and milk quality of small ruminants. In addition, EOs improve antioxidant status in blood serum and rumen fermentation and decrease environmental impact.

Preliminary Investigation of the Effects of Rosemary Extract Supplementation on Milk Production and Rumen Fermentation in High-Producing Dairy Cows

Rosemary extract (RE) has been used as an antioxidant in cosmetics and food additives, indicating its potential as a feed additive to improve adaptation in high-producing dairy cows. Here, we investigated the effects of RE supplementation on lactation performance and rumen fermentation in high-producing dairy cows. Thirty multiparous cows were blocked into 15 groups based on milk production and were randomly assigned to one of two treatments: 0 or 28 g/d of RE supplementation to the basic diet per cow. The experiment was conducted over a 74-day period, which included an initial two-week adaptation period. We observed significant increases in milk and milk lactose yields following RE supplementation. Somatic cell count tended to decrease by treatment. Additionally, superoxide dismutase concentration significantly increased and malonaldehyde level decreased after RE supplementation. Sequencing of 16S rRNA revealed that RE supplementation significantly affected the microbial composition and decreased the richness of the microbiota. Specifically, the abundance of the genus Prevotella was significantly decreased by RE supplementation and was correlated with volatile fatty acids in the Mantel test, whereas no significant correlation was found for other genera. Our findings provide fundamental information on the potential for RE as a feed additive for dairy cows to improve antioxidant status and enhance propionate generation.

Effects of rosemary (Rosmarinus officinalis) by-products and linseed (Linumusitatissimum) intake on digestibility, body weight gain, and estimated tissular composition in cull fat-tailed ewes

The aim of this study was to evaluate the effect of rosemary (Rosmarinus officinalis) residues (RR) as dietary supplement in association with linseed (Linumusitatissimum) on digestive aspects and body weight (BW) gain in fat-tailed Barbarine ewes. To achieve this, 24 cull ewes (BW: 33 ± 2.7 kg) were divided into four groups receiving a basal diet composed of 500 g of straw for two groups (S) and 300 g of straw in addition to 200 g of RR for two other groups (R). All animals received 750 g of concentrate; the usual concentrate (UC) was offered for one S (S-UC) and one R group (R-UC); the linseed concentrate (LC) was also offered for one S (S-LC) and one R group (R-LC). The fattening and digestibility trials lasted 90 days. The dry matter (DM) intake and digestibility were similar across the groups. However, the crude protein (CP) intake and digestibility and the neutral detergent fiber intake were significantly affected by the treatments (P > 0.05). The nitrogen intake (NI), the fecal, and retained nitrogen were significantly affected by the regimen (P < 0.05); however, the urinary nitrogen was unchanged. The nitrogen balance was positive for all groups averaging 60% of the NI. The ruminal pH, ammonia nitrogen, and protozoa concentration were not affected by the RR intake and linseed supply; however, the control time affected significantly these parameters. Final BW, the average daily gain, the muscle, and fat contents were neither affected by the basal diet nor by the concentrate type (P > 0.05). In conclusion, the RR intake in association with linseed did not alter the animal's performances by improving their productive characteristics and consequently, the commercial value of this sheep's category.