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Growing concerns regarding antibiotic use in livestock, due to antibiotic resistance and potential human transmission, have led to increased interest in herbs and their derivatives, including essential oils, which possess antimicrobial properties that may enhance overall productivity and serve as a strategy for methane mitigation. The objective of this meta-analysis was to investigate the effects of adding oregano to the diet in different forms (essential oils, plant materials, or leaves) on the dry matter intake (DMI), milk yield (MY), milk components, nutrient digestibility, ruminal fermentation parameters, and methane (CH4) emissions of dairy cows. A literature search was conducted to identify papers published from 2000 to 2023. Effect size for all outcomes was reported as a standardized means difference (SMD) and raw means difference with 95% confidence intervals. Heterogeneity was determined using the Q test and I2 statistic. The results of the meta-analysis indicated that adding oregano had no effect on DMI (SMD = 0.081; p = 0.507) and MY (SMD = 0.060; p = 0.665). Milk fat percentage, milk protein percentage, and milk lactose percentage were not affected by oregano. The addition of oregano to the diet significantly decreased dry matter digestibility (SMD = −0.502; p = 0.013), crude protein digestibility (SMD = −0.374; p = 0.040), and neutral detergent fiber digestibility (SMD = −0.505; p = 0.014). Ruminal pH (SMD = −0.122; p = 0.411), total volatile fatty acids concentration (SMD = −0.038; p = 0.798), acetate (SMD = −0.046; p = 0.757), propionate (SMD = 0.007; p = 0.960), and butyrate (SMD = 0.037; p = 0.801) proportion were not affected by oregano. The addition of oregano to the diet tended to decrease CH4/DMI (SMD = −0.275; p = 0.095) but did not affect CH4 production (SMD = −0.156; p = 0.282). Heterogeneity (Q and I2) was non-significant for all parameters. We conclude that the inclusion of oregano in various forms (essential oils, plant materials, or leaves) in the diet of dairy cows reduces nutrient digestibility but does not significantly affect DMI, MY, milk components, ruminal fermentation parameters, or CH4 production. Future research should focus on optimizing the dosage of oregano (both EOs and plant materials) and exploring the impact of its form on lactation, nutrient digestibility, ruminal fermentation, and CH4 emissions in dairy cows. [ABSTRACT FROM AUTHOR]

An experiment was conducted to examine how dietary interventions reducing enteric methane (CH4) emissions influence manure CH4 emissions in biogas production (as biochemical methane potential (BMP)) or under static conditions mimicking natural manure storage conditions. Experimental treatments consisted of a factorial arrangement of high (HF: 0.65) or low (LF: 0.35) levels of forage and 0 or 50 g of rapeseed oil per kg of diet dry matter. Oil supplementation reduced daily enteric CH4 emissions, especially in the HF diet, by 20%. Greater dietary concentrate proportion reduced CH4 yield and intensity (6 and 12%, respectively) and decreased pH, increased total volatile fatty acids, and molar proportions of butyrate and valerate in feces incubated under static conditions. Oil supplementation increased daily BMP and BMP calculated per unit of organic matter (OM) (17 and 15%, respectively). Increased dietary concentrate had no impact on daily BMP and BMP per unit of OM, whereas it reduced daily CH4 production by 89% and CH4 per unit of OM by 91% under static conditions. Dietary oil supplementation tended to decrease fecal CH4 production per unit of digestible OM (23%) under static conditions. Diets had no impact on the alpha diversity of ruminal prokaryotes. After incubation, the fecal prokaryote community was significantly less diverse. Diets had no effect on alpha diversity in the BMP experiment, but static trial fecal samples originating from the HF diet showed significantly lower diversity compared with the LF diet. Overall, the tested dietary interventions reduced enteric CH4 emissions and reduced or tended to reduce manure CH4 emissions under static conditions, indicating a lack of trade-off between enteric and manure CH4 emissions. The potential for increasing CH4 yields in biogas industries due to dietary interventions could lead to a sustainable synergy between farms and industry. [ABSTRACT FROM AUTHOR]

The objective of this trial was to determine the amount of alfalfa hay (AH) in low forage diets that could be replaced with dried corn gluten feed (DCGF) without negatively altering eating behaviour, ruminal fermentation, nutrient digestibility, and performance of lactating dairy cows. Eight multiparous Holstein cows were used in a replicated 4 × 4 Latin square design experiment. Treatments included (dry matter [DM] basis): 18.81% AH without DCGF (0DCGF,); 12.53% AH and 6.26% DCGF (6DCGF); 6.26% AH and 12.53% DCGF (12DCGF); and 0% AH and 18.81% DCGF (18 DCGF). Diet particle size and physically effective neutral detergent fibre declined linearly (p <.001) as DCGF replaced AH resulting in a linear decrease (p <.001) in time (min/d) spent eating, ruminating, and chewing. As DCGF replaced AH, ruminal pH decreased linearly (p =.003) and total VFA concentrations increased linearly (p =.02) tending to be highest (p =.062) for 12DCGF. Ruminal acetate and butyrate, and plasma β-hydroxybutyrate concentrations declined linearly (p =.001) whereas ruminal propionate concentration increased linearly (p =.001) as DCGF increased. Dry matter intake (DMI; p =.001) and nutrient digestibility increased linearly (p <.05) and tended to be greatest (p <.10) for 12DCGF. Milk yield (MY; p =.016) and protein yield (p =.001) increased linearly, but milk fat yield declined as DCGF replaced 6 and 12% of AH and decreased more when DCGF replaced all AH resulting in a quadratic response (p =.041). Results of this trial suggest that replacing 12% of the AH with DCGF increases MY because of higher DMI and nutrient digestibility, but replacing all of the AH with DCGF reduces milk fat yield and dairy efficiency. DCGF can replace AH to improve nutrient digestibility and milk yield. Improvements in nutrient digestibility when DCGF replaces AH potentially reduce total waste production of dairy cows. Completely replacing AH with DCGF in low forage diets reduces milk fat yield due to change in ruminal fermentation. [ABSTRACT FROM AUTHOR]

The aim of this paper was to investigate the effects of soybean oil, an oilseed rich in the polyunsaturated fatty acid C18:2, on dry matter intake (DMI), milk yield (MY) and milk composition (including fatty acid profile) of dairy cows by using a meta-analysis approach. In the meta-analysis, effect size for all outcomes was reported as standardised means difference with 95% confidence intervals. Q test and I2 were calculated to detect the heterogeneity, with a meta-regression also used to investigate sources of heterogeneity. Results of the meta-analysis indicated that adding soybean oil to the diet of dairy cows decreased DMI, milk fat percentage (MFP), milk fat yield (MFY) and milk protein percentage (MPP), whilst significantly increasing MY. Unsaturated fatty acids C18:2, C18:1 trans-11 and C18:2 cis-9 trans-11 conjugated linoleic acid (CLA) all significantly increased with soybean oil inclusion in the diet, whereas C18:3 was numerically higher but not significantly different. Milk composition, including MFP, MFY, MPP, short-chain and medium-chain fatty acids (C4–C20) and unsaturated fatty acids showed a significant percentage of heterogeneity. Results of the meta-regression indicated that dose of soybean oil, total fatty acids in the diet, and the concentration of C18:2 between groups receiving soybean oil and control are the most important factors affecting this heterogeneity. By performing meta-analysis and meta-regression it can be concluded that dietary supplementation of soybean oil to lactating dairy cows decreased DMI, and increased MY and the amount of unsaturated fatty acids in milk. Soybean oil dietary supplementation to dairy cows increased milk yield but reduced milk fat content. Milk fat in soybean oil dietary supplemented cows has a lower content of short-chain fatty acids, associated with de novo synthesis. Milk fat in soybean oil dietary supplemented cows has a higher content of C18:1 trans-11, C18:2 and CLA. [ABSTRACT FROM AUTHOR]

Background: herbs are among the feed supplements under investigation that could replace antibiotics to improve humoral and cellular immune response in birds. Objective: this study evaluated the potential of Aloe vera (Aloe barbadensis Miller) and vitamin E as immunostimulants on humoral and cellular immune responses in broilers. Methods: broilers were randomly assigned to three dietary treatments: a negative control (basal diet + with no additive), basal diet + 1% Aloe vera gel in drinking water, and basal diet + 100 mg/Kg vitamin E in the feed. Antibody titers against sheep red blood cells and Newcastle disease virus were used to examine the humoral immune response, whereas cellular immune response was evaluated using the tests. Results: the highest level of antibody titer against sheep red blood cells on examination days 28 and 38, and the highest response to injection of phytohemagglutinin-P on day 38 was observed in the Aloe vera gel group (p<0.05). However, the response of broilers fed Aloe vera gel was not different from those receiving vitamin E (p>0.05). In addition, the greatest antibody level against Newcastle disease virus was obtained on days 25 and 35 in the vitamin E group, with no significant difference from the Aloe vera gel group (p>0.05). Conclusion: in general, our findings demonstrated that both Aloe vera gel and vitamin E can enhance humoral and cellular immune responses of broilers, while Aloe vera gel can be used as an immunostimulant in chickens. [ABSTRACT FROM AUTHOR]

Given the currently increased focus of researchers on applications of medicinal herbs as a natural additives to animal and poultry feed for enhanced performance of the immune system, the present study aims to examine effects of peppermint, Aloe vera, and Vitamin E on immune response in broilers. In this experiment, three hundred one-day old male broilers (Ross 308) were used on a completely randomized design in 4 groups with 5 replicates, each consisting of 15 broilers. The experimental groups included the control group (basal diet with no additive), a group that received 10 g/kg dry peppermint leaves (added to basal diet), a group given 10 g/kg Aloe vera gel (added to basal diet), and a group treated with 100 mg/kg Vitamin E. Evaluation of antibody titer against Newcastle disease virus indicated that on day 27, the highest level of antibody titer was observed in the Vitamin E group, showing a significant difference from other groups (P<0.05) except for the group that received the dry peppermint leaves. On day 37, the highest level of antibody titer against Newcastle disease virus was found in the Vitamin E group with a significant difference compared to the herb groups (the groups that received dry peppermint leaves and Aloe vera gel) as well as the control group (P<0.05). On the other hand, on days 27 and 37, the groups that received dry peppermint leaves and Aloe vera gel showed significant increase in their antibody titer against Newcastle disease virus compared to the control group (P<0.05). The results after injection of phytohemagglutinin-P on day 40 demonstrated that broilers in the Aloe vera gel group and those belonging to the dry peppermint leaves group significantly enhanced their response to phytohemagglutinin-P solution compared to the control group and to the broilers that were given Vitamin E (P<0.05). On day 42, a significant increase was observed in total white blood cell counts of broilers in the Aloe vera gel group and the dry peppermint leaves group compared to the control broilers, although the largest number of white blood cell was found in the broilers that received Vitamin E (p<0.05). In general, our results showed that supplementation of broiler feed with either dry peppermint leaves or Aloe vera gel enhances immune response. [ABSTRACT FROM AUTHOR]

The aim of this study was to estimate the requirement for digestible lysine for broilers from 35 to 49 days of age. Two hundred and forty chicks with a mean weight of 44±1 g were used in a completely randomized design, made up of male and female chicks and 6 digestible lysine levels. Experimental diets were formulated to be isoenergetic and isonitrogenous. Fitted broken lines on different responses indicated break points at 0.93, 0.93 (for body weight), 0.98, and 0.92 for feed conversion ratio for male and female, respectively. The results showed that the digestible lysine requirement of male broilers for maximum breast yield percentage, plasma free lysine and antibody titer against Newcastle disease virus exceeded the range of lysine levels tested. Dietary lysine had a significant effect in increasing the plasma free lysine, albumin, total protein, immunoglobulin, antibody titer against sheep red blood cell, Newcastle disease virus and heterophil to lymphocyte ratio. In conclusion, lysine requirements of broilers for performance were lower than breast yield percentage and immune responses. Broken-line analysis showed that the concentrations of plasma free lysine were useful physiological indicators for determining the digestible lysine requirement of male and female broilers. Our results suggest that the estimated requirements based on exponential response curves were higher than estimated requirements obtained using a broken-line model. [ABSTRACT FROM AUTHOR]

The present study attempts to analyze the effects of different levels of Aloe vera gel as an alternative to antibiotic, on performance and ileum morphology in broilers. Three hundred one-day old Ross 308 male broilers were used on a completely randomized design in 5 groups with 4 replicates, each consisting of 15 broilers. The groups included the control group (basal diet) and three groups with basal diet mixed with different levels of Aloe vera gel (1.5%, 2% and 2.5%). Finally, there was a group with basal diet plus 15 ppm antibiotic virginiamycin. The results obtained regarding performance of the broilers showed that Aloe vera gel groups brought about higher body weight gain and feed intake compared to the control group; however, no significant difference was observed in feed conversion ratio between the groups treated by Aloe vera gel and the control group (P>0.05). Although the antibiotic group showed better performance and heavier dressing percentage than the Aloe vera gel and the control groups, no significant difference was seen between the group treated by 2% Aloe vera gel and the antibiotic group regarding body weight gain, feed conversion ratio and dressing percentage (P>0.05). Among the Aloe vera gel groups, the 2% Aloe vera gel group had the largest villus height and the greatest villus height to crypt depth ratio compared to the antibiotic group (P<0.05). In general, 2% Aloe vera gel treatment may be recommended to achieve the best performance in broilers as an alternative to antibiotic growth promoter. [ABSTRACT FROM AUTHOR]

• Improve starch usage could increase the efficiency of milk yield in the dairy industry. • Substitution of steam flaked (SFC) for finely ground (FGC) corn increased starch digestibility. • Replacing FGC with SFC tended to increase milk yield and reduced milk fat percent. • SFC improve performance, starch digestibility, and nitrogen efficiency of dairy cows. The objective of this meta-analysis was to investigate the effects of substitution of steam flaked corn (SFC) instead of finely ground corn (FGC) on dry matter (DM) intake, nutrients digestibility, milk yield (MY), milk composition, and rumen fermentation of dairy cows. A literature search was conducted to identify papers published from 1990 to 2020. Effect size for all outcomes was reported as standardized means difference (SMD) with 95 % confidence intervals. Heterogeneity was determined using Q test and I2 statistic, while meta-regression was used to examine factors influencing heterogeneity. The meta-analysis results indicated no effect of SFC inclusion on DM intake (SMD = -0.214; 95 % CI = -0.549 to 0.121; P = 0.210). Starch digestibility (SMD = 0.987; 95 % CI = 0.668–1.307; P < 0.001) increased and DM digestibility (SMD = 0.345; 95 % CI = -0.027 to 0.718; P = 0.069) tended to increase as SFC replaced FGC. In this regard, DM digestibility decreased with increasing DM and starch intake, and increased with increasing forage level and days in milk. Milk yield tended to increase (SMD = 0.195; 95 % CI = -0.021 to 0.411; P = 0.077) and milk protein yield and content increased as SFC replaced FGC, but milk fat yield and content decreased. Inclusion of SFC instead of FGC significantly decreased MUN (SMD = -0.332; 95 % CI = -0.659 to -0.005; P = 0.047). Replacing SFC instead of FGC did not influence the ruminal pH (SMD = -0.021; 95 % CI = -0.278 to 0.236; P = 0.871) and total VFA concentration (SMD = -0.092; 95 % CI = -0.359 to 0.174; P = 0.497), however, decreased acetate (SMD = -0.579; 95 % CI = -0.862 to -0.296; P < 0.001), isovalerate (SMD = -0.388; 95 % CI = -0.694 to -0.082; P = 0.013), and isobutyrate (SMD = -0.607; 95 % CI = -0.947 to -0.266; P < 0.001) proportion. Substitution of SFC for FGC decreased the rumen NH 3 concentration (SMD = -1.005; 95 % CI = -1.341 to -0.668; P < 0.001). Egger's test showed publication bias was detected for rumen acetate, propionate, butyrate, valerate, acetate to propionate ratio, and NH 3 (P < 0.1). We conclude that SFC has the potential to impact on lactation performance, digestibility, and rumen fermentation of dairy cows without any negative effect on DM intake and rumen environment, but its effects for some variables depend upon DM intake and forage inclusion rate in diets. [ABSTRACT FROM AUTHOR]

Simple Summary: Methane produced by ruminants contributes to increased greenhouse gas effect. There are various nutritional strategies to reduce methane emission, such as supplementing fat or changing starch levels in the diet. Understanding the interactions of these strategies on methane emission, as well as performance, digestibility, and rumen fermentation is important. The present study aimed to assess the effects of starch level with or without a mixture of sunflower and fish oils on nutrient intake and digestibility, milk yield and composition, rumen fermentation, ruminal CH4 emissions and microbial ecology in dairy cows. Oil mixture rich in polyunsaturated fatty acids supplemented to low- or high-starch diets reduced dry matter intake and increased energy digestibility of lactating cows. High starch level improved nutrient digestibility and tended to reduce ruminal acetate:propionate ratio but did not affect rumen pH, molar propionate ratio, or ruminal CH4 emissions. Oil decreased absolute ruminal CH4 emission or tended to decrease CH4 per energy corrected milk. Four multiparous dairy cows were used in a 4 × 4 Latin square to examine how starch level and oil mixture impact dry matter (DM) intake and digestibility, milk yield and composition, rumen fermentation, ruminal methane (CH4) emissions, and microbial diversity. Experimental treatments comprised high (HS) or low (LS) levels of starch containing 0 or 30 g of a mixture of sunflower and fish oils (2:1 w/w) per kg diet DM (LSO and HSO, respectively). Intake of DM did not differ between cows fed LS and HS diets while oil supplementation reduced DM intake. Dietary treatments did not affect milk and energy corrected milk yields. There was a tendency to have a lower milk fat concentration due to HSO compared with other treatments. Both high starch level and oil supplementation increased digestibility of gross energy. Cows receiving HS diets had higher levels of total rumen VFA while acetate was lower than LS without any differences in rumen pH, or ruminal CH4 emissions. Although dietary oil supplementation had no impact on rumen fermentation, decreased CH4 emissions (g/day and g/kg milk) were observed with a concomitant increase in Anoplodinium-Diplodinium sp. and Epidinium sp. but a decrease in Christensenellaceae, Ruminococcus sp., Methanobrevibacter ruminantium and Mbb. gottschalkii clades. [ABSTRACT FROM AUTHOR]

Mixing nitrogen-stabilizing leguminous forages such as Vicia spp. with livestock feeding systems like farm-pasture or farm-animal systems is one of the best approaches to reserve seasonal feeds, to decrease the load on pasture, and to increase soil fertility. The objective of this study was to determine the chemical compositions and fresh/dry forage yield of three varieties of Vicia spp. (Vicia narbonensis, narbon vetch, accession 2561; Vicia sativa, common vetch, accession 463; Vicia dasycarpa, woolly-pod vetch, accession 2446) at full blooming stage. The plants were grown under the climatic conditions of the province of Lorestan in Western Iran and were harvested at full blooming stage. Fresh and dry forage yields, as well as protein yield, were significantly higher (P<0.05) in narbon vetch (28847, 7366 and 1400 kg per hectare, respectively) than in woolly-pod (24825, 4884 and 1050 kg per hectare, respectively) and common vetch (20727, 6061 and 564 kg per hectare, respectively). Woolly-pod vetch had the highest content of crude protein (21.5%) and ash (12.3%), while common vetch had the highest content of neutral detergent fibre (43.9%). There was no difference in degraded dry matter (DDM) between the Vicia varieties in vitro. Results showed that all the Vicia varieties provide high quality forage for livestock, and can be recommended for cultivation because of their adaptability to the particular conditions of a region. [ABSTRACT FROM AUTHOR]

A meta-analysis was conducted to analyze the effects of different dietary vegetable sources rich in unsaturated FA (UFA) on sheep cheese FA profile. This study also quantified the overall effect of feeding sheep with vegetable sources rich in UFA (linseed, flaxseed, sunflower seed, canola, olive oil, bran oil, and olive cake), on milk yield (MY) and milk composition. A literature search was conducted to identify papers published from 2000 to 2019. Effect size for all parameters was calculated as standardized mean difference. Heterogeneity was determined using I 2 statistic, while meta-regression was used to examine factors influencing heterogeneity. Effect size was not significant for MY, milk fat percentage (MFP), and milk protein percentage (MPP). Dietary inclusion of vegetable sources rich in UFA decreased the effect size for C12:0, C14:0, and C16:0 and increased the effect size for C18:0, C18:1 t-11, C18:1 c-9, C18:2 c-9, t-11, C18:2 n-6, and C18:3 n-3. Heterogeneity was significant for MY, MFP, MPP, and overall cheese FA profile. Meta-regression revealed days in milk as a contributing factor to the heterogeneity observed in MFP and MPP. Meta-regression showed that ripening time is one of the factors affecting cheese FA profile heterogeneity while the type of feeding system(preserved roughages vs. pasture) had no effect on heterogeneity. Overall, inclusion of dietary vegetable sources rich in UFA in sheep diets would be an effective nutritional strategy to decrease saturated FA and increase polyunsaturated FA contents in cheeses without detrimental effects on MY, MFF, and MPP., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Vargas-Bello-Pérez, Darabighane, Miccoli, Gómez-Cortés, Gonzalez-Ronquillo and Mele.)