Lactic acid bacteria to improve growth performance in young calves fed milk replacer and spray-dried whey powder

Recent Developments in the Application of Filamentous Fungus Aspergillus oryzae in Ruminant Feed

The resource-intensive nature of the ruminant farming sector, which has been exacerbated by population growth and increasing pressure to reduce feed antibiotics and growth promoters, has sparked interest in looking for sustainable alternative feed sources to enhance ruminant production efficiency. Edible filamentous fungi, rich in macronutrients like proteins, offer promise in reducing the reliance on conventional protein sources and antimicrobials to improve feed quality and animal performance. The inclusion of single-cell proteins, particularly filamentous fungi, in ruminant feed has long been of scientific and industrial interest. This review focuses on the potential application of the extensively studied Aspergillus oryzae and its fermentation extracts in ruminant nutrition. It provides an overview of conventional ruminant feed ingredients, supplements, and efficiency. Additionally, this review analyzes the re-utilization of organic residues for A. oryzae cultivation and examines the effects of adding fungal extracts to ruminant feed on ruminal digestibility and animal performance, all within a circular bioeconomy framework.

Holstein calves fed a milk replacer with a direct fed microbial (DFM) and a starter containing a botanical extract or a DFM alone or in combination

Botanical extracts (BE; Apex, Adisseo, North America) have demonstrated enhanced DMI and improved gut health, while direct fed microbials (DFM), such as Lactobacillus acidophilus fermentation product (EX: Excell, Pacer Technology, Inc.), has demonstrated improved gut health and growth performance of growing Holstein calves. The hypothesis was this combination may be synergistic to neonatal calf growth performance and intestinal health. Eighty, 2-5-d old Holstein bull calves were blocked by BW and randomly assigned to one of 8 treatments arranged in a 2 × 4 factorial using a randomized complete block design. The main factors were milk replacer (MR) without (Control) and with EX added at 5 g/d fed and calf starter (CS). The CS containing no additives (Control); CS containing BE at 496 mg/kg; CS containing EX at 2.50 g/kg; and CS containing BE and EX at the same inclusion rates. The MR were fed 2x/d at 0630 and 1800 h along with free choice CS (amounts and orts weighed d) and water. Weaning occurred after d 42 for the 56-d experiment. No MR by CS main effects interactions were detected for BW, ADG, CS intake, total DMI, feed efficiency or body frame gain parameters. The BW gain (38.0 and 39.3 kg for control and EX, respectively) for MR main effect was similar for calves fed both MR, while CS main effects (38.7, 39.7, 39.2, and 37.2 kg for control, BE, EX, and BE&EX, respectively) was similar among all CS. Gains in body length (10.6 and 10.8 cm), hip width (4.5 and 4.5 cm), withers height, (10.5 and 10.6 cm) heart girth (18.6 and 19.9 cm) and body length (9.1 and 7.9 cm) were similar for calves fed both MR, while CS main effects for hip height (10.5, 10.2, 10.3, and 10.9 cm), hip width (4.7, 4.6, 4.4, and 4.3 cm) withers height (10.7, 10.9, 10.3 and 10.6 cm), heart girth (19.9, 18.9, 18.9, and 19.4 cm), and body length (11.7, 9.1, 8.3, and 8.4 cm) were similar. Total days of a fecal score = 0 was greater for calves fed Control MR and BE CS compared with calves fed Contol MR and the combination of BE&EX with calves fed the remaining treatments being intermediated and similar. This study demonstrated little calf growth performance and health benefits when feeding a BE or EX alone or in combination compared with calves fed control.

Invited review: "Probiotic" approaches to improving dairy production: Reassessing "magic foo-foo dust"

The gastrointestinal microbial consortium in dairy cattle is critical to determining the energetic status of the dairy cow from birth through her final lactation. The ruminant's microbial community can degrade a wide variety of feedstuffs, which can affect growth, as well as production rate and efficiency on the farm, but can also affect food safety, animal health, and environmental impacts of dairy production. Gut microbial diversity and density are powerful tools that can be harnessed to benefit both producers and consumers. The incentives in the United States to develop Alternatives to Antibiotics for use in food-animal production have been largely driven by the Veterinary Feed Directive and have led to an increased use of probiotic approaches to alter the gastrointestinal microbial community composition, resulting in improved heifer growth, milk production and efficiency, and animal health. However, the efficacy of direct-fed microbials or probiotics in dairy cattle has been highly variable due to specific microbial ecological factors within the host gut and its native microflora. Interactions (both synergistic and antagonistic) between the microbial ecosystem and the host animal physiology (including epithelial cells, immune system, hormones, enzyme activities, and epigenetics) are critical to understanding why some probiotics work but others do not. Increasing availability of next-generation sequencing approaches provides novel insights into how probiotic approaches change the microbial community composition in the gut that can potentially affect animal health (e.g., diarrhea or scours, gut integrity, foodborne pathogens), as well as animal performance (e.g., growth, reproduction, productivity) and fermentation parameters (e.g., pH, short-chain fatty acids, methane production, and microbial profiles) of cattle. However, it remains clear that all direct-fed microbials are not created equal and their efficacy remains highly variable and dependent on stage of production and farm environment. Collectively, data have demonstrated that probiotic effects are not limited to the simple mechanisms that have been traditionally hypothesized, but instead are part of a complex cascade of microbial ecological and host animal physiological effects that ultimately impact dairy production and profitability.

Effect of direct-fed microbials on growth performance, blood biochemical indices, and immune status of female goats

The effect of direct-feed microbial (DFM) treatment on body weight, serum biochemical indexes, serum immunoglobulins, and serum cytokines was studied. The study was a completely randomized design with 20 growing females Beichuan white goats, weighing 25.11 ± 1.96 kg, divided into two groups of 10 goats per treatment. Goats were offered (1) 10 mL saline solution (Control group) (2) or 10 mL microbials solution (DFM group) on days 0 and 7 for two times. No effect on final body weight and body size was observed between DFM and control group (p > 0.05). DFM treatment had greater serum total protein, globulin, and albumin/globulin ratio than the control treatment (p < 0.05). The concentrations of IgA, IgG, IgM, INF-γ, and IL-2 in DFM group were significantly higher than those in the control group on days 7, 14, and 21 (p < 0.05), and the highest content was detected on day 14 of the experiment. The concentrations of IgA, IgG, IgM, IL-2, INF-γ, INF-α, IL-4, and IL-5 in DFM group on day 14 were higher than those on day 0 (p < 0.05). In conclusion, DFM enhanced serum immunoglobulins and cytokines without affecting body weight, body size, and normal serum metabolism.

Modulating gastrointestinal microbiota to alleviate diarrhea in calves

The calf stage is a critical period for the development of heifers. Newborn calves have low gastrointestinal barrier function and immunity before weaning, making them highly susceptible to infection by various intestinal pathogens. Diarrhea in calves poses a significant threat to the health of young ruminants and may cause serious economic losses to livestock farms. Antibiotics are commonly used to treat diarrhea and promote calf growth, leading to bacterial resistance and increasing antibiotic residues in meat. Therefore, finding new technologies to improve the diarrhea of newborn calves is a challenge for livestock production and public health. The operation of the gut microbiota in the early stages after birth is crucial for optimizing immune function and body growth. Microbiota colonization of newborn animals is crucial for healthy development. Early intervention of the calf gastrointestinal microbiota, such as oral probiotics, fecal microbiota transplantation and rumen microbiota transplantation can effectively relieve calf diarrhea. This review focuses on the role and mechanisms of oral probiotics such as Lactobacillus, Bifidobacterium and Faecalibacterium in relieving calf diarrhea. The aim is to develop appropriate antibiotic alternatives to improve calf health in a sustainable and responsible manner, while addressing public health issues related to the use of antibiotics in livestock.

The Effect of Dietary Supplementation with Zinc Amino Acids on Immunity, Antioxidant Capacity, and Gut Microbiota Composition in Calves

The aim of this study was to investigate the effect of dietary supplementation with zinc (Zn) amino acids at different concentrations on immunity, antioxidant capacity, and gut microbiota composition in calves. Twenty-four one-month-old healthy Angus calves of comparable body weight were randomly divided into three groups (four males and four females in each group) based on the amount of Zn supplementation added to the feed the animals received: group A, 40 mg/kg DM; group B, 80 mg/kg DM; and group C, 120 mg/kg DM. The experiment ended when calves reached three months of age (weaning period). The increase in dietary Zn amino acid content promoted the growth of calves, and the average daily weight gain increased by 36.58% (p < 0.05) in group C compared with group A. With the increase in the content of dietary Zn amino acids, the indexes of serum immune functions initially increased and then decreased; in particular, the content of immunoglobulin M in group A and group B was higher than that in group C (p < 0.05), whereas the content of interleukin-2 in group B was higher than that in the other two groups (p < 0.05). In addition, the content of superoxide dismutase and total antioxidant capacity in the serum of calves in group B was higher than that in group C (p < 0.05), and the MDA level was lower than in group C (p < 0.05). Moreover, alpha diversity in the gut microbiota of calves in group B was higher than that in group A and group C (p < 0.05); the dominant phyla were Firmicutes and Bacteroidota, whereas the dominant genera were Unclassified-Lachnospiraceae and Ruminococcus. Linear discriminant analysis showed that the relative abundance of Bacteroides in the gut microbiota of calves in group B was higher than that in group A, and the relative abundance of Prevotellaceae-UCG-003 was higher compared to that in experimental group C. Thus, dietary supplementation of 80 mg/kg of Zn amino acids to calves could improve the immune function and antioxidant capacity, as well as enrich and regulate the equilibrium of gut microbiota, thus promoting the healthy growth of calves.

An Evaluation of Nutritional and Therapeutic Factors Affecting Pre-Weaned Calf Health and Welfare, and Direct-Fed Microbials as a Potential Alternative for Promoting Performance—A Review

The priority for calf rearing has been to maintain good health and welfare in order to promote and sustain future production. However, there have been numerous reports of undesirable levels of morbidity and mortality amongst pre-weaned calves. This may be mitigated or exacerbated by nutritional management practices. Some areas of concern include colostrum feeding, utilization of waste milk, and restrictive milk feeding regimes. Antibiotics may be prescribed at lethal or sub-inhibitory doses to treat or prevent disease. However, extensive antibiotic use may disrupt the gastrointestinal microbiota and aid in expanding the antibiotic resistant gene pool. In an attempt to reduce the use of antibiotics, there is a demand to find alternative performance enhancers. Direct-fed microbials, also known as probiotics, may comply with this role. A DFM consists of live microorganisms that are biologically active and able to confer health benefits onto the host. Lactic acid bacteria have been the most frequently investigated; however, this field of research has expanded to include spore-forming bacteria and live yeast preparations. This review aims to provide a comprehensive evaluation of the nutritional management strategies that may increase a calf’s susceptibility to morbidity and mortality, the efficacy and sustainability of antibiotics as a tool for managing calf health and welfare, and the potential for DFMs as a supportive strategy for promoting calf wellbeing.

Effects of Milk Replacer-Based Lactobacillus on Growth and Gut Development of Yaks' Calves: a Gut Microbiome and Metabolic Study

The gut microbiota and its metabolic activities are crucial for maintaining host homoeostasis and health, of which the role of probiotics has indeed been emphasized. The current study delves into the performance of probiotics as a beneficial managemental strategy, which further highlights their impact on growth performance, serologic investigation, gut microbiota, and metabolic profiling in yaks' calves. A field experiment was employed consisting of 2 by 3 factorial controls, including two development stages, namely, 21 and 42 days (about one and a half month), with three different feeding treatments. Results showed a positive impact of probiotic supplements on growth performance by approximately 3.16 kg (P < 0.01) compared with the blank control. Moreover, they had the potential to improve serum antioxidants and biochemical properties. We found that microorganisms that threaten health were enriched in the gut of the blank control with the depletion of beneficial bacteria, although all yaks were healthy. Additionally, the gut was colonized by a microbial succession that assembled into a more mature microbiome, driven by the probiotics strategy. The gut metabolic profiling was also changed significantly after the probiotic strategy, i.e., the concentrations of metabolites and the metabolic pattern, including enrichments in protein digestion and absorption, vitamin digestion and absorption, and biosynthesis of secondary metabolites. In summary, probiotics promoted gut microbiota/metabolites, developing precise interventions and achieving physiological benefits based on intestinal microecology. Hence, it is important to understand probiotic dietary changes to the gut microbiome, metabolome, and the host phenotype. IMPORTANCE The host microbiome is a composite of the trillion microorganisms colonizing host bodies. It can be impacted by various factors, including diet, environmental conditions, and physical activities. The yaks' calves have a pre-existing imbalance in the intestinal microbiota with an inadequate feeding strategy, resulting in poor growth performance, diarrhea, and other intestinal diseases. Hence, targeting gut microbiota might provide a new effective feeding strategy for enhancing performance and maintaining a healthy intestinal environment. Based on the current findings, milk replacer-based Lactobacillus feeding may improve growth performance and health in yaks' calves.

Biological Functions of Exopolysaccharides from Lactic Acid Bacteria and Their Potential Benefits for Humans and Farmed Animals

Lactic acid bacteria (LAB) synthesize exopolysaccharides (EPS), which are structurally diverse biopolymers with a broad range of technological properties and bioactivities. There is scientific evidence that these polymers have health-promoting properties. Most commercialized probiotic microorganisms for consumption by humans and farmed animals are LAB and some of them are EPS-producers indicating that some of their beneficial properties could be due to these polymers. Probiotic LAB are currently used to improve human health and for the prevention and treatment of specific pathologic conditions. They are also used in food-producing animal husbandry, mainly due to their abilities to promote growth and inhibit pathogens via different mechanisms, among which the production of EPS could be involved. Thus, the aim of this review is to discuss the current knowledge of the characteristics, usage and biological role of EPS from LAB, as well as their postbiotic action in humans and animals, and to predict the future contribution that they could have on the diet of food animals to improve productivity, animal health status and impact on public health.

Different methods of eubiotic feed additive provision affect the health, performance, fermentation, and metabolic status of dairy calves during the preweaning period

Background

This study aimed to evaluate whether different methods of providing eubiotic feed additives to neonatal calves, during the preweaning period, can improve the calves’ health, performance, ruminal fermentation, and metabolic status. Forty-four (3-day-old) Holstein–Friesian dairy calves (22 female and 22 male) were divided into four treatment groups for the duration of the 8-week trial. The eubiotic feed additive consisted of a combination of probiotic Lactobacillus spp. (multiple-strains at a dose of 250 mg/calf/day) and phytobiotics containing rosmarinic acid, as the main bioactive compound (at a dose of 50 mg/calf/day). The groups were named: CON (control, without eubiotic in either the milk replacer or the starter feed), MR (eubiotic in the milk replacer), SF (eubiotic in the starter feed), MRS (eubiotic in both the milk replacer and the starter feed). The individual intake of starter feed and the fecal scores were measured daily, and body weight and biometric measurements were taken weekly until calves were 56 days of age. Blood samples were collected on day 3 and then every 14 days to determine concentrations of insulin-like-growth-factor-I, β-hydroxybutyrate, non-esterified fatty acids, and blood urea nitrogen. Ruminal fluid was collected on days 28 and 56 for short-chain fatty acids, NH₃-N, and pH measurements.

Results

The body weight of the calves of the MR treatment group was higher compared to all other groups on days 28 and 56. Including the eubiotic feed additive in the milk replacer increased average daily gain, starter intake, and total dry matter intake from day 29 to day 56 and the overall experimental period compared to the CON group. The calves with MR treatment had lower fecal scores from days 3 to 28, a number of parasite oocysts/cysts per gram of feces on day 28, and the occurrences of fecal consistency scores of 3 (mild diarrhea) and 4 (severe diarrhea) were 3.2 and 3.0 times lower, respectively, compared with the CON group. The MR group had higher ruminal concentrations of short-chain-fatty-acids, propionate, and butyrate on day 56 than the CON group. Adding eubiotics into milk replacer resulted in the highest concentrations of blood insulin-like-growth-factor-I and β-hydroxybutyrate from days 29 to 56 and the overall experimental period.

Conclusion

The addition of eubiotic feed additives into the milk replacer can improve health, performance, ruminal fermentation, and biochemical blood indices in dairy calves during the preweaning period.

Influence of microbial probiotics on ruminant health and nutrition: sources, mode of action and implications

Globally, ruminant production contributes immensely to the supply of the highest quality and quantity of proteins for human consumption, sustenance of livelihoods, and attainment of food security. Nevertheless, the phasing out of antibiotics in animal production has posed a myriad of challenges, including poor growth, performance and nutrient utilization, pathogen colonization, dysbiosis, and food safety issues in ruminants. Probiotics (direct-fed microbials), comprising live microbial strains that confer health and nutritional benefits to the host when administered in appropriate quantities, are emerging as a viable, safe, natural and sustainable alternative to antibiotics. Although the mechanisms of action exerted by probiotics on ruminants are not well elucidated, dietary probiotic dosage to ruminants enhances development and maturation, growth and performance, milk production and composition, nutrient digestibility, feed efficiency, pathogen reduction, and mitigation of gastrointestinal diseases. However, the beneficial response to probiotic supplementation in ruminants is not consistent, being dependent on the microbial strain selected, combination of strains, dose, time and frequency of supplementation, diet, animal breed, physiological stage, husbandry practice, and farm management. Nonetheless, several studies have recently reported beneficial effects of probiotics on ruminant performance, health and production. This review conclusively re-iterates the need for probiotics inclusion for the sustainability of ruminant production. Considering the role that ruminants play in food production and employment, global acceptance of sustainable ruminant production through supplementation with probiotics will undoubtedly ensure food security and food safety for the world. © 2021 Society of Chemical Industry.

Autochthonous Limosilactobacillus reuteri BFE7 and Ligilactobacillus salivarius BF17 probiotics consortium supplementation improves performance, immunity, and selected gut health indices in Murrah buffalo calves

Probiotics have emerged as biotherapeutic adjuncts to combat neonatal calf gastrointestinal disorders. Therefore, they are considered a suitable alternative to antibiotics for maintaining a healthy and balanced gut microbiota. Hence, the current investigation was carried out to evaluate the effect of autochthonous probiotics on Murrah buffalo calves. Sixteen calves (5-7 days of age) were randomly divided into four groups. Group I served as control (CT), fed a basal diet with no supplementation. Groups II (LR), III (LS), and IV (CS) were supplemented with Limosilactobacillus reuteri BF-E7, Ligilactobacillus salivarius BF-17, and a consortium of both probiotic strains at a rate of 1x10⁸ CFU/g/calf per day along with the basal diet, respectively. Two previously isolated potential probiotic strains, Limosilactobacillus reuteri BF-E7 and Ligilactobacillus salivarius BF-17, were found to be compatible in vitro. Dietary supplementation of probiotics for sixty days significantly increased (P<0.05) dry matter intake (DMI, g/d), average daily gain (ADG, g/d), net body weight gain (kg), feed conversion efficiency (FCE), and structural growth measurements as compared to control. Furthermore, a considerable (P<0.05) increase in the abundance of beneficial intestinal microbiota (lactobacilli and bifidobacteria) was observed along with improvement in fecal biomarkers like lactate and ammonia, immune status, and reduced fecal score. Upon comparative analysis among treatment groups, the results were found to be better in the probiotic consortium fed group compared to the LR and LS treated groups. The present findings conclusively deduced that autochthonous probiotic consortium might serve as potential candidate for fostering performance, immunity, and gut health biomarkers in Murrah buffalo calves.

Effects of a multi-strain probiotic on growth, health, and fecal bacterial flora of neonatal dairy calves

OBJECTIVE

The aim of this study was to investigate the effects of dietary supplementation with a multi-strain probiotic (MSP) product containing of Bifidobacterium animalis, Lactobacillus casei, Streptococcus faecalis, and Bacillus cerevisiae on growth, health, and fecal bacterial composition of dairy calves during the first month of life.

METHODS

Forty Holstein calves (24 female and 16 male) at 2 d of age were grouped by sex and date of birth then randomly assigned to 1 of 4 treatments: milk replacer supplementation with 0 g (0MSP), 2 g (2MSP), 4 g (4MSP), and 6 g (6MSP) MSP per calf per day.

RESULTS

Supplementation of MSP did not result in any significant differences in parameters of body measurements of calves during the 30 d period. As the dosage of MSP increased, the average daily gain (p = 0.025) and total dry matter intake (p = 0.020) of calves showed a linear increase. The fecal consistency index of the 2MSP, 4MSP, and 6MSP group calves were lower than that of the 0MSP group calves (p = 0.003). As the dosage of MSP increased, the concentrations of lactate dehydrogenase (p = 0.068) and aspartate aminotransferase (p = 0.081) in serum tended to decrease, whereas the concentration of total cholesterol increased quadratically (p = 0.021). The relative abundance of Dorea in feces was lower (p = 0.011) in the 2MSP, 4MSP, and 6MSP group calves than that in the 0MSP group calves. The relative abundance of Dorea (p = 0.001), Faecalibacterium (p = 0.050), and Mitsuokella (p = 0.030) decreased linearly, whereas the relative abundance of Prevotella tended to increase linearly as the dosage of MSP increased (p = 0.058).

CONCLUSION

The MSP product can be used to reduce the diarrhea, improve the performance, and alter the composition of the fecal bacteria in neonatal dairy calves under the commercial conditions.

Effects of probiotic administration on the digestibility characteristics and growth performance of finishing beef cattle fed a total mixed ration containing different levels of corn stover

In this study, we aimed to assess the effects of probiotic administration on the digestibility characteristics and growth performance of finishing beef cattle fed a total mixed ration (TMR) containing different levels of corn stover. One hundred and sixty Simmental × Continental crossbred bulls were randomly allocated to two animal houses (80 bulls each) and randomly assigned four TMR differing in the level of corn stover-high (HCT) and low (LCT)-with or without probiotics in each animal house. Feeding HCT supplemented with probiotics increased (P < 0.05) the apparent digestibility of crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), and acid detergent fiber (ADF). Regardless of probiotic supplementation, the nitrogen intake and fecal nitrogen levels of animals fed HCT were lower than those fed LCT (P < 0.05). Additionally, feeding probiotics increased (P < 0.05) the efficiency of ruminal fermentation, final body weight, and average daily gain (ADG) of animals, with this effect being stronger in animals fed HCT. In conclusion, supplementing probiotics with HCT has a positive effect on the growth of finishing beef cattle, thereby providing economic benefits.

Effects of compound probiotics on growth performance, rumen fermentation, blood parameters, and health status of neonatal Holstein calves

This study aimed to investigate the effects of compound probiotics (consisting of 10⁸ cfu/g of Lactobacillus plantarum, 10⁸ cfu/g of Pediococcus acidilactici, 10⁸ cfu/g of Pediococcus pentosaceus, 10⁷ cfu/g of and Bacillus subtilis) on growth performance, rumen fermentation, bacteria community, blood parameters, and health status of Holstein calves at the first 3 mo of age. Forty-eight newborn calves were randomly divided into the following 3 groups: control group (milk replacer with no compound probiotics), low compound probiotics group (milk replacer + 0.12 g of compound probiotics per head per day), and high compound probiotics group (HP; milk replacer + 1.2 g of compound probiotics per head per day). Starter pellets of the low compound probiotics and HP groups were coated with 0.05% compound probiotics. Milk replacer was provided from 2 to 63 d of age (6 L at 2-10 d, 8 L at 11-42 d, 6 L at 43-49 d, 4 L at 50-56 d, and 2 L at 57-63 d), and starter pellets were provided ad libitum from 7 to 90 d of age. Body weight and body size (d 1, 30, 60, and 90), blood (d 40 and 80), and rumen fluid (d 90) were analyzed using the one-way ANOVA procedure; fecal score was recorded daily and analyzed as repeated measures using the mixed model procedure. Results showed that diet supplemented with compound probiotics had no effects on the body weight, average daily gain, dry matter intake, and feed efficiency. At 90 d of age, diet supplemented with compound probiotics decreased the withers height. Immunity activities increased in the HP group, supported by the increased concentrations of serum total protein and immunoglobulins at 40 d of age, and by the increased activity of superoxide dismutase at 80 d of age. Diet supplemented with compound probiotics altered rumen fermentation, indicated by the decreased rumen acetic acid and propionic acid, and the increased butyric acid concentrations. Diet supplemented with compound probiotics improved the health status of calves, indicated by the decreased fecal score at 3 wk of age and the decreased medicine treatments. In summary, although diet supplemented with HP decreased the withers height, this level of probiotics is recommended to improve rumen development and health status of newborn Holstein calves.

Implication and challenges of direct-fed microbial supplementation to improve ruminant production and health

Direct-fed microbials (DFMs) are feed additives containing live naturally existing microbes that can benefit animals' health and production performance. Due to the banned or strictly limited prophylactic and growth promoting usage of antibiotics, DFMs have been considered as one of antimicrobial alternatives in livestock industry. Microorganisms used as DFMs for ruminants usually consist of bacteria including lactic acid producing bacteria, lactic acid utilizing bacteria and other bacterial groups, and fungi containing Saccharomyces and Aspergillus. To date, the available DFMs for ruminants have been largely based on their effects on improving the feed efficiency and ruminant productivity through enhancing the rumen function such as stabilizing ruminal pH, promoting ruminal fermentation and feed digestion. Recent research has shown emerging evidence that the DFMs may improve performance and health in young ruminants, however, these positive outcomes were not consistent among studies and the modes of action have not been clearly defined. This review summarizes the DFM studies conducted in ruminants in the last decade, aiming to provide the new knowledge on DFM supplementation strategies for various ruminant production stages, and to identify what are the potential barriers and challenges for current ruminant industry to adopt the DFMs. Overall literature research indicates that DFMs have the potential to mitigate ruminal acidosis, improve immune response and gut health, increase productivity (growth and milk production), and reduce methane emissions or fecal shedding of pathogens. More research is needed to explore the mode of action of specific DFMs in the gut of ruminants, and the optimal supplementation strategies to promote the development and efficiency of DFM products for ruminants.

Effects of mannan-oligosaccharide and Bacillus subtilis supplementation to preweaning Holstein dairy heifers on body weight gain, diarrhea, and shedding of fecal pathogens

The objective of this clinical trial was to evaluate the effectiveness of probiotic, prebiotic, and synbiotic supplementation on average daily weight gain (ADG), duration of diarrhea, age at incidence of diarrhea, fecal shedding of Cryptosporidium oocysts, enteric pathogens, and the odds of pneumonia in preweaning dairy heifer calves on a commercial dairy. Feeding prebiotics and probiotics may improve health and production of calves. Hence, healthy Holstein heifer calves (n = 1,801) from a large California dairy were enrolled at 4 to 12 h of age and remained in this study until weaning at 60 d of age. Calves were block randomized to 1 of 4 treatments: (1) control, (2) yeast culture enriched with mannan-oligosaccharide (prebiotic), (3) Bacillus subtilis (probiotic), and (4) combination of both products (synbiotic), which were fed in milk twice daily from enrollment until weaning. Serum total protein at enrollment and body weight at 7, 42, and 56 d of age were measured. Fecal consistency was assessed daily for the entire preweaning period. A subgroup of 200 calves had fecal samples collected at 7, 14, 21, and 42 d for microbial culture and enumeration of Cryptosporidium oocysts by direct fluorescent antibody staining. Synbiotic-treated calves had 19 g increased ADG compared with control calves for overall ADG, from 7 to 56 d. From 42 to 56 d, prebiotic-treated calves had 85 g greater ADG and synbiotic-treated calves had 78 g greater ADG than control calves. There was no difference in duration of the first diarrhea episode, hazard of diarrhea, or odds of pneumonia per calf with treatment. Probiotic-treated calves had 100 times lower fecal shedding of Cryptosporidium oocysts at 14 d and prebiotic-treated calves had fewer Escherichia coli and pathogenic E. coli at 42 d compared with control calves. Although there were no effects on duration of diarrhea or pneumonia incidence, greater ADG in the late preweaning period may reflect treatment effects on enteric pathogens during the rearing process. The decreased shedding of Cryptosporidium should reduce infectious pressure, environmental contamination, and public health risks from Cryptosporidium. Our findings suggest ADG and potential health benefits for calves fed prebiotics, probiotics, and synbiotics and can help the dairy industry make informed decisions on the use of these products in dairy production.

Lactobacillus plantarum GB LP-1 as a direct-fed microbial for neonatal calves

Direct-fed microbial feed additives with potential to enhance growth performance, gut health, and immunity have gained considerable popularity in neonatal calf production. Lactobacillus plantarum GB LP-1 (LP) produced by a proprietary fermentation process could be a viable direct-fed microbial feed for neonatal calves. The hypothesis was that feeding LP may ease transitioning from milk replacer (MR) to calf starter (CS) by improving gut health and appetite, while minimizing health challenges from pathogens and stress to improve growth performance. The experimental objective was to evaluate LP in an MR feeding program at 3 inclusion rates. Fifty-one 2- to 5-d-old Holstein bull calves were randomly assigned to 1 of 3 treatments using a randomized complete block design. Treatments were (1) Control (LP0): LP fed at 0 g/d; (2) LP4: LP fed at 4 g/d; and (3) LP8: LP fed at 8 g/d. Calves were fed MR at 0.57 kg/d for 14 d via bucket, which was increased to 0.85 kg/d until 35 d, and were then fed once daily at 0.425 kg/d with weaning after d 42 of the 56-d experiment. Calves were fed at 0630 and 1800 h in equal allotments, with access at all times to free-choice water and a pelleted CS with 25.5% crude protein. Calves demonstrated a linear growth response to increasing LP inclusion rate: calves fed LP8 gained more body weight (33.0, 36.9, and 37.7 kg for LP0, LP4, and LP8, respectively) than calves fed LP0, with calves fed LP4 being intermediate and similar. The 0-to-42-d (MR feeding phase) average daily gain (ADG; 562.9, 595.9, and 655.7 g/d) and 0-to-56-d ADG (588.6, 658.4, and 673.0 g/d) demonstrated linear responses, with calves fed LP8 having greater ADG than calves fed LP0, and calves fed LP4 being intermediate and similar. Total CS intake was similar among calves fed all treatments (66.3, 69.0, and 72.5 kg/56 d), which resulted in a quadratic response in feed efficiency (0.50, 0.53, and 0.52 kg of gain/kg of dry matter) for calves fed LP4 compared with calves fed LP0, with calves fed LP8 being intermediate and similar. Fecal scores improved linearly with increasing LP inclusion rate. These data demonstrate that feeding Lactobacillus plantarum GB LP-1 to neonatal calves improves gut health to increase growth performance at 4 and 8 g/d, while feed efficiency was greatest at 4 g/d.

Probiotic microorganisms and herbs in ruminant nutrition as natural modulators of health and production efficiency – a review

Probiotics, prebiotics, synbiotics, direct-fed microbials, and herbs may improve the production efficiency in ruminants. The beneficial effect of selected specific microbes on animal health is reflected in protection against pathogens, stimulation of immunological response, increased production capacity, and mitigation of stress effects. Phytobiotic plants used in the nutrition of ruminant animals increase feed palatability. This in turn has a positive effect on feed intake and, consequently, increases production performance. Pectins, terpenes, phenols, saponins, and antibioticlike substances contained in phytobiotics prevent irritation, diarrhea, and increase the activity of digestive enzymes. Thanks to the abundance of biologically active substances such as flavonoids, glycosides, coumarins, carotenoids, polyphenols, etc., phytobiotics exhibit immunostimulatory and antioxidant properties as well. Given such a wide range of effects on health status and production parameters in animals, an attempt was made in this review to compile the current knowledge on the possible application of these natural growth stimulants in ruminant nutrition and to demonstrate their potential benefits and/or risks for breeding these animals.

Effect of the administration of Lactobacillus spp. strains on neonatal diarrhoea, immune parameters and pathogen abundance in pre-weaned calves

Neonatal calf diarrhoea is one of the challenges faced by intensive farming, and probiotics are considered a promising approach to improve calves' health. The objective of this study was to evaluate the effect of potential probiotic lactobacilli on new-born dairy calves' growth, diarrhoea incidence, faecal score, cytokine expression in blood cells, immunoglobulin A (IgA) levels in plasma and faeces, and pathogen abundance in faeces. Two in vivo assays were conducted at the same farm in two annual calving seasons. Treated calves received one daily dose of the selected lactobacilli (Lactobacillus reuteri TP1.3B or Lactobacillus johnsonii TP1.6) for 10 consecutive days. A faecal score was recorded daily, average daily gain (ADG) was calculated, and blood and faeces samples were collected. Pathogen abundance was analysed by absolute qPCR in faeces using primers directed at Salmonella enterica, rotavirus, coronavirus, Cryptosporidium parvum and three Escherichia coli virulence genes (eae, clpG and Stx1). The faecal score was positively affected by the administration of both lactobacilli strains, and diarrhoea incidence was significantly lower in treated calves. No differences were found regarding ADG, cytokine expression, IgA levels and pathogen abundance. Our findings showed that oral administration of these strains could improve gastrointestinal health, but results could vary depending on the calving season, which may be related to pathogen seasonality and other environmental effects.

Systematic review of an intervention: the use of probiotics to improve health and productivity of calves

The aims of this study were to undertake a systematic review and meta-analysis of the types of probiotic formulations that are commercially available and to critically appraise the available evidence for the effectiveness of probiotics in improving the health and productivity of calves. Relevant papers were identified to answer the question: 'In calves aged between birth to one year, is the use of probiotics associated with changes in haematological or biochemical parameters, faecal bacteria counts, average daily live weight gain, dry matter intake, or feed conversion ratio?' The search of the literature yielded 67 studies that fit the primary screening criteria. Included studies were assessed for bias and confounding using a predefined risk assessment tool adapted from the Cochrane Collaboration's tool for assessing risk of bias in randomised trials and GRADE guidelines. Meta-analysis was performed using Review Manager and R. Random sequence generation was low in more than 59 % of studies. Risk of allocation concealment and performance bias were largely unclear in over 68 % of studies. Calves fed probiotics had increased average daily live weight gains (ADG) from birth to weaning (mean difference [MD] = 83.14 g/d 95 % CI = 58.36-107.91, P < 0.001) compared with calves on a control diet. Calf age reduced the level of heterogeneity of the effect of probiotics on ADG for calves between one to three weeks of age (τ² = 73.15; I² = 4%; P = 0.40) but not for calves older than three weeks of age (τ² = 2892.91; I² = 73 %; P < 0.001). Feed conversion ratio (FCR) was lower for calves on probiotics (MD = -0.13 kg of dry matter intake (DMI) to kg of live weight (LW) gain, 95 % CI = -0.17 to -0.09, P < 0.001), and the heterogeneity of effect was large in younger aged calves (τ² = 0.05; I² = 78 %; P = 0.03). The risk of bias regarding the methodology in the included studies was high. The quality of evidence for each outcome was categorised as moderate. There is sufficient data to support the effectiveness of probiotic use in some applications such as for the improvement of performance and productivity parameters of calves. However, the evidence is weak for other potential probiotic uses in calves such as improved health and reduced risk of disease. Therefore, the existing data are inconclusive and do not support the use of probiotics as an alternative to antimicrobials to improve calf health and productivity.

Effect of dietary supplementation of Lactobacillus acidophilus on blood biochemical profile, antioxidant activity and plasma immunoglobulin level in neonatal Murrah buffalo calves

An experiment was designed to evaluate the effect of dietary supplementation of Lactobacillus acidophilus on blood biochemical profile, antioxidant activity and plasma immunoglobulin level in neonatal Murrah buffalo calves. The 90 day trial was conducted on 24 neonatal Murrah buffalo calves randomly divided into 4 dietary treatments, viz. CON (basal diet alone), T1 (basal diet + L. acidophilus as a fermented milk @ 100 mL/calf/day having 108 CFU/mL), T2 (basal diet + L. acidophilus as a fermented milk @ 200 mL/calf/day having 108 CFU/ml) and T3 (basal diet + L. acidophilus as a fermented milk @ 300 ml/calf/day having 108 CFU/mL). Supplementation of probiotics improved the plasma glucose level in T2 and T3 as compared to CON. Total protein (TP), plasma albumin (A), plasma globulin (G) and A:G ratio did not change with the supplementation of probiotic in calves. Total cholesterol and HDL cholesterol levels in plasma remained same in all the 4 groups. Total antioxidant (TA) activity was higher in T2 and T3 as compared to CON, whereas it was intermediate in T1. Super oxide dismutase (SOD) activity was significantly higher in T1, T2 and T3 groups as compared to CON whereas catalase and glutathione peroxidase (GPx) activity remained same in all groups throughout experimental period. The total plasma immunoglobulin and plasma IgG remained uninfluenced in all the groups. In conclusion, supplementation of L. acidophilus improved energy metabolism and antioxidant capacity in neonatal Murrah buffalo calves.

Nutraceuticals: An Alternative Strategy for the Use of Antimicrobials

Livestock industries strive to improve the health of their animals and, in the future, they are going to be required to do this with a continued reduction in antimicrobial use. Nutraceuticals represent a group of compounds that may help fill that void because they exert some health benefits when supplemented to livestock. This review is focused on the mechanisms of action, specifically related to the immune responses and health of ruminants. The nutraceutical classes discussed include probiotics, prebiotics, phytonutrients (essential oils and spices), and polyunsaturated fatty acids.

Current status and application of lactic acid bacteria in animal production systems with a focus on bacteria from honey bee colonies

Lactic acid bacteria (LAB) are widely distributed in nature and, due to their beneficial effects on the host, are used as probiotics. This review describes the applications of LAB in animal production systems such as beekeeping, poultry, swine and bovine production, particularly as probiotics used to improve health, enhance growth and reproductive performance. Given the importance of honeybees in nature and the beekeeping industry as a producer of healthy food worldwide, the focus of this review is on the coexistence of LAB with honeybees, their food and environment. The main LAB species isolated from the beehive and their potential technological use are described. Evidence is provided that 43 LAB bacteria species have been isolated from beehives, of which 20 showed inhibition against 28 species of human and animal pathogens, some of which are resistant to antibiotics. Additionally, the presence of LAB in the beehive and their relationship with antibacterial properties of honey and pollen is discussed. Finally, we describe the use of lactic bacteria from bee colonies and their antimicrobial effect against foodborne pathogens and human health. This review broadens knowledge by highlighting the importance of honeybee colonies as suppliers of LAB and functional food.

Conjugated linoleic acid producing potential of lactobacilli isolated from goat (AXB) rumen fluid samples

OBJECTIVE

The present investigation was aimed to explore the potential of lactobacilli for conjugated linoleic acid (CLA) production, isolated from rumen fluid samples of lactating goats.

METHODS

A total of 64 isolates of lactobacilli were obtained using deMan-Rogosa-Sharpe (MRS) agar from rumen fluid of goats and further subjected to morphological and biochemical characterizations. Isolates found as gram-positive, catalase negative rods were presumptively identified as Lactobacillus species and further confirmed by genus specific polymerase chain reaction (PCR). The phylogenetic tree was constructed from the nucleotide sequences using MEGA6.

RESULTS

Out of the 64 isolates, 23 isolates were observed positive for CLA production by linoleate isomerase gene-based amplification and quantitatively by UV-spectrophotometric assay for the conversion of linoleic acid to CLA as well as gas chromatography-based assay. In all Lactobacillus species cis9, trans11 isomer was observed as the most predominant CLA isomer. These positive isolates were identified by 16S rRNA gene-based PCR sequencing and identified to be different species of L. ingluviei (2), L.salivarius (2), L. curvatus (15), and L. sakei (4).

CONCLUSION

The findings of the present study concluded that lactic acid bacteria isolated from ruminal fluid samples of goat have the potential to produce bioactive CLA and may be applied as a direct fed microbial to enhance the nutraceutical value of animal food products.

Growth, health, rumen fermentation, and bacterial community of Holstein calves fed Lactobacillus rhamnosus GG during the preweaning stage1

The aim of this study was to determine if feeding Lactobacillus rhamnosus GG (GG, ATCC 53013) to neonatal calves would alter their growth, health, rumen fermentation, and bacterial community composition during the preweaning stage; we hypothesized that it would. Twenty-four male Holstein calves were blocked and randomly assigned to 1 of 2 treatment groups: 1) untreated control (CON), or 2) treated with 1 × 1010 cfu/d of a GG suspension (GG). Calves received GG daily, mixed with the milk replacer in the morning feed for 6 wk. Starter and alfalfa hay intakes, as well as feces and respiratory scores, were recorded daily, while body weight and structures were measured weekly. Blood, rumen fluid, and feces samples were collected, from which relevant indicators were detected. The results showed that the administration of GG significantly increased voluntary starter intake (P = 0.023) and ADG (P = 0.035) of the calves. The fecal score (P = 0.018) was lower and the β-hydroxybutyric concentration in the plasma tended to increase (P = 0.092) in calves treated with GG. The pH of the rumen fluid in calves fed GG was lower (P = 0.007), which might be attributable to the tendency (P = 0.083) for total volatile fatty acids concentration to increase. Administration of GG significantly increased the amylase, protease activity, and the microbial protein concentrations (P = 0.043, P = 0.036, and P = 0.044, respectively) in the rumen fluids. Furthermore, GG treatment altered the dominant bacteria order and relative abundance of the bacteria families in the rumen fluids. The microbial diversity indices were significantly affected by GG administration. In conclusion, the neonatal calves fed GG before weaning increased their voluntary starter intake and growth performance, improved the rumen fermentation, and regulated the pattern to normally increase the propionate and butyrate concentrations. Administration of GG also diversified the bacterial community composition in the rumen, and regulated the balance of rumen and intestinal microorganisms. These results indicated that feeding calves GG were beneficial to the rumen development and early weaning.

Benefits and Inputs From Lactic Acid Bacteria and Their Bacteriocins as Alternatives to Antibiotic Growth Promoters During Food-Animal Production

Resistance to antibiotics is escalating and threatening humans and animals worldwide. Different countries have legislated or promoted the ban of antibiotics as growth promoters in livestock and aquaculture to reduce this phenomenon. Therefore, to improve animal growth and reproduction performance and to control multiple bacterial infections, there is a potential to use probiotics as non-antibiotic growth promoters. Lactic acid bacteria (LAB) offer various advantages as potential probiotics and can be considered as alternatives to antibiotics during food-animal production. LAB are safe microorganisms with abilities to produce different inhibitory compounds such as bacteriocins, organic acids as lactic acid, hydrogen peroxide, diacetyl, and carbon dioxide. LAB can inhibit harmful microorganisms with their arsenal, or through competitive exclusion mechanism based on competition for binding sites and nutrients. LAB endowed with specific enzymatic functions (amylase, protease…) can improve nutrients acquisition as well as animal immune system stimulation. This review aimed at underlining the benefits and inputs from LAB as potential alternatives to antibiotics in poultry, pigs, ruminants, and aquaculture production.

Probiotic properties of native Lactobacillus spp. strains for dairy calves

The use of native microorganisms with probiotic capacity is an alternative tool for the treatment and prevention of several diseases that affect animals, such as neonatal calf diarrhoea. The selection of probiotic strains within a collection is based on different in vitro and in vivo assays, which predict their potential. The aim of this study was to characterise a group of native Lactobacillus spp. strains isolated from faeces of healthy calves using an in vitro approach and to assess their ability to colonise the gastrointestinal tract (GIT) of calves. Native Lactobacillus spp. strains were evaluated on their capacity to survive low pH conditions and bile salts presence, biofilm formation and adhesion to both mucus and Caco-2 cells. Based on the in vitro characterisation, four strains (Lactobacillus johnsonii TP1.1, Lactobacillus reuteri TP1.3B, L. johnsonii TP1.6 and Lactobacillus amylovorus TP8.7) were selected to evaluate their capacity to colonise and persist in the GIT of calves. The assessment of enteric persistence involved an in vivo assay with oral administration of probiotics and quantification in faeces of the administered bacterial species with real-time quantitative PCR (qPCR). The study was conducted using 15 calves (1-month-old) which were divided into five groups of three animals, four of which were treated with four different selected strains and one was the control group. Strains TP1.3B and TP1.6 managed to persist in treated animals until ten days after the end of the administration period, indicating that they could be promising candidates for the design of probiotics for calves.

Effects of dietary supplementation with two alternatives to antibiotics on intestinal microbiota of preweaned calves challenged with Escherichia coli K99

The aim of this study was to investigate the effects of dietary supplementation with two alternatives to antibiotics (Candida tropicalis and mulberry leaf flavonoids) on intestinal microbiota of preweaned calves challenged with Escherichia coli K99. Sixty Holstein calves were randomly assigned to 5 treatments: fed a basal diet (N-CON); fed a basal diet and challenged with E.coli K99 (P-CON); fed a basal diet supplemented with C.tropicalis (CT), mulberry leaf flavonoids (MLF), and the combination of the two additives (CM), respectively, and challenged with E.coli K99. The MLF and CM groups had significantly higher average daily grain and feed efficiency, and significantly lower fecal scores compared with the P-CON group after E. coli K99 challenge. The supplementation groups increased the relative abundance, at the phylum level, of Bacteroidetes and Proteobacteria, whereas at the genus level, they increased the relative abundance of Prevotella, Lactobacillus, and Enterococcus. Quantitative PCR revealed that the CT, MLF, and CM groups had significantly lower copy numbers of E.coli K99 compared with the P-CON group. The CT, MLF, and CM treatments reduce days of diarrhea, improve intestinal health, and beneficially manipulate the intestinal microbiota in preweaned calves.

Effect of probiotic Bacillus amyloliquefaciens strain H57 on productivity and the incidence of diarrhoea in dairy calves

A spore-forming probiotic, Bacillus amyloliquefaciens strain H57 (H57), was administered to dairy calves in starter pellets to determine effects on liveweight gain, feed conversion efficiency and animal health under summer feeding conditions, without antibiotics. Twenty-four male and female calves were allocated into two groups and from 4 weeks of age individually offered 6 L/day of whole milk and ad libitum starter pellets impregnated with H57 (3.16 × 108 cfu per kg DM) or without (Control) until 12 weeks of age. The calves were housed in a non-air-conditioned animal house, with deep-straw bedding over concrete, under typically challenging subtropical summer conditions. After 12 weeks the calves were released into a grazing paddock as one group and were supplemented ad libitum with control pellets and hay, until 19 weeks of age. From Weeks 4 to 12, liveweight and feed intakes were measured weekly and health status was monitored daily. Rumen fluid and blood were collected at Weeks 4 and 12, and to test for persistence after cessation of feeding H57, each were measured again at Week 19. From Weeks 4 to 12, the H57 calves grew faster (767 vs 551 g/day, P = 0.01), tended to consume more pellets (1013 vs 740 g DM/day, P = 0.07) and were 19% more feed conversion efficiency (2.43 vs 2.90 kg milk + starter DM/kg weight gain, P = 0.01) compared with the Control calves. The mean duration of each diarrhoea event was 2 days less for the H57 calves than the Control (P = 0.01). The H57 calves weaned 9 days earlier (P = 0.02) and were heavier at Week 19 (155 vs 139 kg, P = 0.03) than the Control calves. The only effect of H57 on rumen volatile fatty acid concentrations was an elevation in valerate at Week 12 (4.10 vs 2.47 mmol/L, P = 0.03). Plasma β-hydroxy butyrate was also elevated in the H57 calves at Week 19 (0.24 vs 0.20 mmol/L), indicating the potential of H57 to improve rumen development. H57 can be used to improve the nutritional performance and reduce the risk of diarrhoea in dairy calves as they transition from milk to dry feed.

Production responses of reproducing ewes to a by-product-based diet inoculated with the probiotic Bacillus amyloliquefaciens strain H57

The potential application of the spore-forming probiotic Bacillus amyloliquefaciens strain H57 (H57) as a novel probiotic for ruminants was evaluated in reproducing ewes. Performance responses were determined by delivering H57 in a pelleted diet based mainly on palm kernel meal (PKM) and sorghum grain. PKM is an agro-industrial by-product with a reputation for poor palatability and the availability of the starch in sorghum grain can be limited in ruminants. The hypothesis was that H57 improves the feeding value of a relatively low quality concentrate diet. Twenty-four first-parity white Dorper ewes were fed PKM-based pellets manufactured with or without H57 (109 cfu/kg pellet) in late pregnancy. During this phase of late pregnancy, the H57 ewes ate 17% more dry matter (1019 vs 874 g/day, P = 0.03), gained more weight (194 vs 30 g/day, P = 0.008) and retained more nitrogen (6.13 vs 3.34 g/day, P = 0.01), but produced lambs with a similar birthweight (4.1 vs 4.2 kg, P = 0.73). Rumen fluid collected from H57 ewes in late pregnancy had higher pH (7.1 vs 6.8, P = 0.07), acetate : propionate ratio (3.4 vs 2.7, P = 0.04), lower ammonia (69 vs 147 mmol/L, P = 0.001) and total volatile fatty acid concentrations (40 vs 61 mg/L, P = 0.02). The digestibility of dry matter, organic matter and fibre were similar between the two groups. The lambs of the H57 ewes grew faster than those of the Control ewes for the first 21 days of lactation (349 vs 272 g/day, P = 0.03), but not thereafter. H57 can improve feed intake and maternal liveweight gain in late pregnancy of first-parity ewes fed a diet based on PKM.

Design of a beneficial product for newborn calves by combining Lactobacilli, minerals, and vitamins

Diarrhea is one of the most frequent diseases affecting newborn calves in intensive systems. Several strategies were proposed to protect and improve health, such as probiotics. This work was directed to design a product containing freeze-dried bacteria, vitamins, and minerals, as well as to optimize conditions with lyoprotectors, combine strains and add vitamins, minerals, and inulin to the product. The lyoprotectors were milk, milk-whey, and actose, and products were stored for 6 months at 4°C. Combined bacteria were freeze-dried in milk and the final products were added with minerals, vitamins, and insulin. The viable cells were determined by the plate count assay and antibiotic profiles to differentiate strains. Lactobacillus johnsonii CRL1693, L. murinus CRL1695, L. mucosae CRL1696, L. salivarius CRL1702, L. amylovorus CRL1697, and Enterococcus faecium CRL1703 were evaluated. The optimal conditions were different for each strain. Milk and milk whey maintained the viability during the process and storage after 6 months for most of the strains, except for L. johnsonii. Lactose did not improve cell's recovery. L. murinus was viable for 6 months in all the conditions, with similar results in enterococci. In strains combined before freeze-dried, the viability decreased deeply, showing that one-step process with bacteria mixtures, vitamins, and minerals were not adequate. Freeze-dried resistance depends on each strain and must be lyophilized individually.

Oral administration of Lactobacillus plantarum and Bacillus subtilis on rumen fermentation and the bacterial community in calves

The objective of this study was to assess the effect of dietary probiotics on rumen fermentation and the bacterial community in dairy calves. Twelve Holstein calves were randomly allocated to three treatments: a basal diet, the basal diet supplemented with Lactobacillus plantarum GF103 (LB) or basal diet supplemented with a mixture of Lactobacillus plantarum GF103 and Bacillus subtilis B27 (LBS). A milk replacer was fed to calves from 8 days of age. A starter and alfalfa hay was offered ad libitum from 21 and 28 days of age, respectively, and the orts were weighted daily. The ruminal fluid was sampled at 56 and 83 days of age to determine the rumen fermentation characteristics. The bacterial community was analyzed by denaturing gradient gel electrophoresis (DGGE) and the number of certain bacteria was quantified by real-time polymerase chain reaction. The ratio of total dry matter intake to average body wieght was higher in the control (P < 0.05). The DGGE fingerprint of the 16S ribosomal RNA gene was affected by the blended probiotics at 83 days of age. The number of Ruminococcus albus was lower in the LB and LBS treatment (P < 0.05). Oral administration of the probiotics affected the rumen bacterial community and the numbers of cellulolytic bacteria decreased.

Desempenho de bezerros leiteiros recebendo probiótico contendo Bacillus subtilis e Bacillus licheniformis

RESUMO Foram utilizados 24 bezerros que receberam 4L/dia de sucedâneo, além de livre acesso a água e concentrado até a 8a semana. Os animais foram distribuídos em delineamento de blocos casualizados, em dois tratamentos: 1) Controle: sem a suplementação de probiótico; 2) Suplementação de 2g/d de Bacillus subtilis e Bacillus licheniformis via sucedâneo lácteo. Semanalmente os animais foram pesados e foram aferidas as medidas corporais; também foram realizadas colheitas de sangue para determinação de glicose, proteína total, ureia e albumina, além de hematócrito. Foram colhidas amostras de fezes semanalmente para contagem de bactérias ácido láticas e enterobactérias e determinação de pH fecal. O peso corporal, o ganho de peso médio diário e as medidas corporais não foram alteradas pela suplementação; muito embora tenham apresentado efeito significativo de idade dos animais. O escore fecal, pH fecal e consumo de concentrado diário também não foram afetados pela suplementação. No entanto, o consumo de concentrado e o pH fecal sofreram influência da idade em resposta ao crescimento natural dos bezerros. A contagem de bactérias ácido láticas foi maior em número do que a contagem de enterobactérias durante todo o período. Apenas as enterobactérias sofreram efeito da idade, enquanto as bactérias ácido láticas permaneceram variando, porém dentro de um padrão constante. Os parâmetros sanguíneos também não foram afetados pela suplementação com probiótico mas todos, com a exceção da albumina, tiveram influência da idade. A suplementação com o probiótico não apresentou benefícios no desempenho ou no metabolismo de bezerros leiteiros, também não reduziu a ocorrência de casos de diarreia.

Probiotic effect on calves infected with Salmonella Dublin: haematological parameters and serum biochemical profile

The aim of this study was to evaluate the effect of a probiotic/lactose inoculum on haematological and immunological parameters and renal and hepatic biochemical profiles before and during a Salmonella Dublin DSPV 595T challenge in young calves. Twenty eight calves, divided into a control and probiotic group were used. The probiotic group was supplemented with 100 g lactose/calf/d and 1010 cfu/calf/d of each strain of a probiotic inoculum composed of Lactobacillus casei DSPV318T, Lactobacillus salivarius DSPV315T and Pediococcus acidilactici DSPV006T throughout the experiment. The pathogen was administered on day 11 of the experiment, at an oral dose of 109 cfu/animal (LD50). Aspartate aminotransferase (AST), gamma glutamyl transpeptidase (GGT), urea, red blood cells, haemoglobin, haematocrit, mean cell haemoglobin (MCH), mean corpuscular volume, mean corpuscular haemoglobin concentration (MCHC), white blood cells, lymphocytes, neutrophils, band neutrophils, monocytes, eosinophils, basophils and the neutrophils/lymphocytes ratio were measured on days 1, 10, 20 and 27 of the experiment. In addition, animals were necropsied to evaluate immunoglobulin A (IgA) production in the jejunal mucosa. The most significant differences caused by the administration of the inoculum/lactose were found during the acute phase of Salmonella challenge (9 days after challenge), when a difference between groups in neutrophils/lymphocytes ratio were detected. These results suggest that the probiotic/lactose inoculum administration increases the calf’s ability to respond to the disease increasing the systemic immune response specific. No differences were found in haemoglobin, haematocrit, MCH, MCHC, AST, urea, GGT, band neutrophils, eosinophils, monocytes and IgA in the jejunum between the two groups of calves under the experimental conditions of this study. Further studies must be conducted to evaluate different probiotic/pathogens doses and different sampling times, to achieve a greater understanding of the effects of this inoculum on intestinal infections in young calves and of its mechanism of action.

Influence of selected feed supplements on the growth and health of calves depending on the sex, season of birth, and number of the dam’s lactations

The aim of this study was to prove the hypothesis that the growth and health of calves are dependent on feed supplements with an antidiarrhoeic effect, in relation to sex, season of birth, and number of the dam’s lactations. A total of 186 calves were included in the experiment. After birth the calves were divided into three treatment groups:Ascophyllum nodosum(brown seaweed hydrolyzate, prebiotics),Lactobacillus sporogenes(probiotics), and the control group. All calves were weighed within two h after birth. The growth and health were investigated from the birth to the fourth week of age. Compared to the control, a significant effect of applied feed supplements was found in theLactobacillus sporogenesgroup in the body weight at 28 days of life (P< 0.01) and in the average daily gains (P< 0.001). Differences between sexes were found in the body weight at birth (P< 0.001) and in the body weight at 28 days of life (P< 0.01). The effect of the season of birth was recorded in the average daily gains (P< 0.01). The effect of the number of the dam’s lactations on calf was proved in body weights at birth and 28 days of life (P< 0.01). The interaction between treatment and sex (P< 0.05), and between treatment and season of birth (P< 0.01) were calculated in the average daily gains. We concluded from the analysis that only the use ofLactobacillus sporogeneshad a positive influence on increasing the growth. Neither of the two supplements had a positive impact on the health of calves.

Effect of Probiotics/Prebiotics on Cattle Health and Productivity

Probiotics/prebiotics have the ability to modulate the balance and activities of the gastrointestinal (GI) microbiota, and are, thus, considered beneficial to the host animal and have been used as functional foods. Numerous factors, such as dietary and management constraints, have been shown to markedly affect the structure and activities of gut microbial communities in livestock animals. Previous studies reported the potential of probiotics and prebiotics in animal nutrition; however, their efficacies often vary and are inconsistent, possibly, in part, because the dynamics of the GI community have not been taken into consideration. Under stressed conditions, direct-fed microbials may be used to reduce the risk or severity of scours caused by disruption of the normal intestinal environment. The observable benefits of prebiotics may also be minimal in generally healthy calves, in which the microbial community is relatively stable. However, probiotic yeast strains have been administered with the aim of improving rumen fermentation efficiency by modulating microbial fermentation pathways. This review mainly focused on the benefits of probiotics/prebiotics on the GI microbial ecosystem in ruminants, which is deeply involved in nutrition and health for the animal.

Probiotics and broiler growth performance: a meta-analysis of randomised controlled trials

1. The aim of this meta-analysis was to investigate the effects of probiotics on the growth performance of broilers. PubMed, Scopus and Scholar Google databases were searched in all languages from 1980 to 2012. The studies in the meta-analysis were only selected if they were randomised and controlled experiments using broilers without apparent disease and the results were published in peer-reviewed journals. 2. A total of 48 and 46 studies were included to assess probiotic effects on body weight gain (BWG) and feed efficiency (FE), respectively. Probiotics increased BWG compared to controls (SMD = 0.661, 95% CI 0.499 to 0.822) and improved FE (SMD = - 0.281, 95% CI -0.404 to -0.157) in the pooled standardised mean difference random effect model, considering the source of heterogeneity and publication biases. However, there are evidences of publication bias and heterogeneity, so the results of this meta-analysis should be considered with caution. Applying the Duval and Tweedie's trim-and-fill methods, the adjusted value for BWG was 0.0594 (95% CI -0.122 to 0.242), and the adjusted value for FE did not show any modifications. 3. The meta-analysis showed that application of probiotics via water resulted in greater BGW and FE than administration through the feed. The effect was not related to the use of mono-strain or multi-strain probiotics, although it may depend on the strain used. The number of broilers and the duration of the experiments had an impact on the outcomes. 4. Additional studies should be conducted with the aim to identify the covariates which can explain the differences in the estimated effect sizes.

A mixture of Lactobacillus casei, Lactobacillus lactis, and Paenibacillus polymyxa reduces Escherichia coli O157:H7 in finishing feedlot cattle

A direct-fed microbial (DFM) containing Paenibacillus polymyxa, Lactobacillus casei, and Lactobacillus lactis was fed to cattle (n = 120) to determine impacts on shedding and survival of Escherichia coli O157:H7 in feces. Cattle were individually penned and fed diets containing 0 (control), 4 × 10(7) CFU (DFM-4), 8 × 10(7) CFU (DFM-8), or 1.2 × 10(8) CFU (DFM-12) lactobacilli per kg of dietary dry matter over 84-day fall-winter growing and 140-day spring-summer finishing periods. Fecal grab samples were collected from cattle at 28-day intervals, E. coli O157:H7 was detected by immunomagnetic separation, and isolates were compared by pulsed-field gel electrophoresis. During the growing period, feces negative for E. coli O157 from each dietary treatment were inoculated with 10(5) CFU/g nalidixic acid-resistant E. coli O157:H7 and were incubated at 4 and 22(u) C for 11 weeks. Fecal pH and fecal dry matter were measured on days 0, 1, 3, and 7 and weekly thereafter, with E. coli O157:H7 enumerated through dilution plating. Treatment with DFMs did not affect survival of E. coli O157:H7 in feces or fecal pH (P > 0.05). Only one steer was positive for E. coli O157:H7 during the growing period, but during the finishing period, DFM-8 and DFM-12 reduced the prevalence of E. coli O157:H7 in feces (P < 0.05). Feeding DFMs also reduced the frequency of individual steers shedding E. coli O157:H7 during finishing (P < 0.05), with control steers shedding E. coli O157:H7 up to four times, whereas DFM-12 steers shed E. coli O157:H7 a maximum of twice. Treatment with DFMs influenced pulsed-field gel electrophoresis profiles; steers that were fed DFM-8 and DFM-12 shed more diverse subtypes of E. coli O157:H7 than did control or DFM-4 steers. Because a companion study found linear improvement in performance with increasing dosage of DFMs in the first 28 days of the growing period, targeted use of DFM-12 during this time and for the final 1 or 2 weeks prior to slaughter may optimize performance and reduce E. coli O157:H7 while minimizing feed costs.

Pathogen translocation and histopathological lesions in an experimental model of Salmonella Dublin infection in calves receiving lactic acid bacteria and lactose supplements

The purpose of this study was to evaluate the capacity of a lactic acid bacteria (LAB) inoculum to protect calves with or without lactose supplements against Salmonella Dublin infection by evaluating histopathological lesions and pathogen translocation. Fifteen calves were divided into three groups [control group (C-G), a group inoculated with LAB (LAB-G), and a group inoculated with LAB and given lactose supplements (L-LAB-G)] with five, six, and four animals, respectively. The inoculum, composed of Lactobacillus (L.) casei DSPV 318T, L. salivarius DSPV 315T, and Pediococcus acidilactici DSPV 006T, was administered with milk replacer. The LAB-G and L-LAB-G received a daily dose of 10⁹ CFU/kg body weight of each strain throughout the experiment. Lactose was provided to the L-LAB-G in doses of 100 g/day. Salmonella Dublin (2 × 10¹⁰ CFU) was orally administered to all animals on day 11 of the experiment. The microscopic lesion index values in target organs were 83%, 70%, and 64.3% (p < 0.05) for the C-G, LAB-G, and L-LAB-G, respectively. Administration of the probiotic inoculum was not fully effective against infection caused by Salmonella. Although probiotic treatment was unable to delay the arrival of pathogen to target organs, it was evident that the inoculum altered the response of animals against pathogen infection.

Scientific Opinion on the welfare of cattle kept for beef production and the welfare in intensive calf farming systems

Information given in previous Opinions "Welfare of cattle kept for beef production" (SCAHAW, 2001) and "The risks of poor welfare in intensive calf farming systems" (EFSA, 2006) is updated and recent scientific evidence on the topics reviewed. Risks of poor welfare are identified using a structured analysis, and issues not identified in the SCAHAW (2001) beef Opinion, especially effects of housing and management on enteric and respiratory diseases are reviewed. The Opinion covers all systems of beef production, although the welfare of suckler cows or breeding bulls is not considered. The Chapter on beef cattle presents new evidence and recommendations in relation to heat and cold stress, mutilations and pain management, digestive disorders linked to high concentrate feeds and respiratory disorders linked to overstocking, inadequate ventilation, mixing of animals and failure of early diagnosis and treatment. Major welfare problems in cattle kept for beef production, as identified by risk assessment, were respiratory diseases linked to overstocking, inadequate ventilation, mixing of animals and failure of early diagnosis and treatment, digestive disorders linked to intensive concentrate feeding, lack of physically effective fibre in the diet, and behavioural disorders linked to inadequate floor space, and co-mingling in the feedlot. Major hazards for white veal calves were considered to be iron-deficiency anaemia, a direct consequence of dietary iron restriction, enteric diseases linked to high intakes of liquid feed and inadequate intake of physically effective fibre, discomfort and behavioural disorders linked to inadequate floors and floor space.