Evaluation of Feed Additives in Animal Production

This study aimed to verify the potential of calcium lactate for the performance, blood index, shinbone quality, jejunal immunity, and egg quality of aged laying hens. A total of 360 62-week-old Hy-Line Brown laying hens were randomly divided into four treatments, with six replicates and 15 chickens per replicate. Experimental groups were fed with 0.25%, 0.5%, and 1.0% calcium lactate to substitute limestone in the control group (maintaining the same amount of calcium). The feeding trial lasted for 12 weeks. The laying rate and daily egg mass of laying hens fed the diets supplemented with calcium lactate was increased relative to those of the control group. The dietary addition of calcium lactate for laying hens enhanced the eggshell ratio, eggshell thickness, eggshell strength, and albumen height of eggs, and the addition level of 0.5% had the best effect. Dietary calcium lactate increased the number of red blood cells, corpuscular hemoglobin, mononuclear leucocytes and basophilic granulocytes, and decreased heterophils in the blood of laying hens. The activities of serum alanine transaminase and creatine kinase in laying hens was reduced by the dietary addition of calcium lactate. Calcium lactate supplementation in diets increased the serum calcium and phosphorus contents of laying hens. The dietary inclusion of calcium lactate increased the contents of IgA, IgG, lysozyme, and sIgA in the jejunal mucosa, and the 0.5% addition level worked best, but the IL-2 content decreased. The addition of 0.5% calcium lactate to the diet reduced the maximal force of the shinbone and increased the work required for shinbone rupture in laying hens. In conclusion, the dietary addition of calcium lactate improved the performance and egg quality of laying hens, probably by its positive effects on body health, intestinal digestible ability, calcium bioavailability, and jejunal mucosal immunity. The optimum amount of calcium lactate in the diet of laying hens is recommended to be 0.5%. Full article

To evaluate the effect of exogenous phytase (Ronozyme HiPhos-L, produced by the strain of Aspergillus oryzae), 1050 one-day-old Ross-308 broilers with an initial average body weight of 50.29 ± 0.98 g were randomly assigned to one of seven dietary treatments with 10 replicates and 15 chicks/cage. During starter (d 1–7), grower (d 8–21), and finisher (d 21–35) periods, broilers were allowed to feed: positive control (PC), negative control (NC), and NC diet supplemented with 250, 500, 1000, 1500, and 3000 U/kg of phytase. Broilers fed NC diet supplemented with graded levels of phytase (250 U/kg to 3000 U/kg) showed a linear increase (p < 0.05) in body weight gain and feed intake during the starter and the overall trial period with no adverse effect on feed conversion ratio. The nutrient utilization of broilers showed neither an increase nor a decrease with the PC and NC diet until d 35 but when the NC diet was supplemented with a graded dose of phytase, the broilers showed a linear increase (p < 0.05) in dry matter, gross energy, calcium (Ca), ash, and phosphorus (P) utilization and a tendency to increase (p < 0.10) nitrogen retention at the end of the starter phase. Unlike the starter phase, broilers fed the PC diet showed increased (p < 0.05) ash and Ca retention at the end of the grower and finisher phase compared to those fed the NC diet. In addition, the phytase group showed a linear increase (p < 0.05) in ash, Ca, and P utilization at the end of d 21 and 35. Moreover, the inclusion of graded levels of phytase in the NC diet showed a linear increase (<0.0001) in bone (ash, Ca, and P) mineralization in broilers. Also, they showed a linear increase (p < 0.05) in gizzard weight, breast muscle, color of lightness, redness, and pH and a decreased cooking loss and drip loss. Though the standard diets were able to compensate for the P deficiency and promote performance and bone mineralization, the elevated (1000 FTU/kg) levels of phytase in the NC diet showed a higher response. Thus, we suggest that incorporating the exogenous enzyme phytase into the broiler feed in excess of 1000 units (U)/kg would be more beneficial to achieve better productivity. Full article

The main purpose of the present research was to evaluate the effect of varying levels of DA inclusion in maternal diet, in the form of powder, on the born-weaning growth performance (days 1–30) and intestinal health of neonatal rabbits. A total of 152 delivered maternal does (3.94 ± 0.05 kg) were allocated into four groups, with thirty-eight replicates of one doe each, and fed with a control diet (CON) supplemented with different levels of powdered DA (85 mg/kg (DA85), 170 mg/kg (DA170), and 340 mg/kg (DA340)) during lactation. The results show that dietary DA increased individual body weight at days 21 and 30 (p = 0.03 and p < 0.01) and showed a linear and quadratic effect on individual body weight and average daily gain (ADG) (p < 0.05), although ADG was not affected by DA. The serum progesterone (P) (p = 0.05) and glutathione peroxidase (GSH-Px) (p = 0.01) concentrations of maternal rabbits were increased in all maternal DA-supplemented groups and showed a linear and quadratic effect (p < 0.05), while a linear effect was observed in estrogen (E-2) (p < 0.05). Interestingly, the concentrations of the serum insulin-like growth factor-1 (IGF-I) (p < 0.01) and immunoglobulin (IgA and IgG) (p < 0.01 and p = 0.01) in neonatal rabbits were increased in all dietary DA groups, and both showed a linear and quadratic effect (p < 0.05). In addition, the serum interleukin (IL-1β) (p = 0.03) and catalase (CAT) (p = 0.04) concentrations were affected by DA supplements, but linear and quadratic effects were only observed in the catalase (CAT) of neonatal rabbits (p < 0.05). Importantly, the duodenal and jejunal villus heights (p < 0.04 and p = 0.01) and the ratio of villus height to crypt depth (p = 0.02 and p = 0.01) in neonatal rabbits were elevated in all DA-supplemented treatments, while a linear and quadratic effect was observed in jejunum, but a quadratic effect was observed in duodenum (p < 0.05). The ileal villus height (p < 0.01) was also elevated in all DA-supplemented treatments exhibiting both linear and quadratic effects (p < 0.05). Moreover, the expression levels of occludin (p = 0.04), zonula occludens-1 (ZO-1) (p < 0.01), IGF-1 (p = 0.03), and solute carrier family 5 member 9 (SCL5A9) (p < 0.01) in jejunum were markedly elevated in the DA175 and 340 mg/kg DA-supplemented groups and were showing linear and quadratic effects (p < 0.05). Finally, inflammation-related gene expression levels such as NF-κB, TLR4, and MYD88 in jejunal (p = 0.01, p = 0.04, and p < 0.01) and ileal (p = 0.04, p = 0.04, and p = 0.03) epithelium were decreased in the DA170 and DA340 groups (p < 0.05), while linear and quadratic effects were observed for TLR4 in jejunum and for NF-κB and TLR4 MYD88 in ileum (p < 0.05). In summary, as a functional additive, maternal DA supplementation with 170 and 340 mg/kg DA during lactation can promote the growth of neonatal rabbits, which is related to improved antioxidative capacity and immunity, as well as improved intestinal health in neonatal rabbits. Full article

A series of four broiler performance studies were conducted in different facilities to investigate the efficacy of a novel bacterial 6-phytase added at 500 FTU/kg diet on growth performance, bone mineralization and precaecal digestibility of phosphorus (pcdP) in broilers fed diets deficient in available P (avP) and calcium (Ca). The experimental design was the same for all studies, with each having three treatments: positive control (PC) diet formulated to meet or exceed the requirements of birds, negative control (NC) diet similarly reduced by 0.15% points in avP and Ca compared to the PC diet, and the NC diet supplemented with phytase (PHY) at 500 FTU/kg diet from 1 to 35 days of age. Body weight (BW) and feed intake were measured at 21 and 35 days of age, and average daily gain (ADG), average daily feed intake (ADFI), feed conversion ratio (FCR), BW gain-corrected-FCR (cFCR), mortality and European performance efficiency factor (EPEF) were calculated. Tibia dry matter, tibia ash content and pcd of P were measured at 21 days of age in all experiments. The analysis of the data from the four experiments showed that compared with birds fed the adequate-nutrient diet, birds fed the NC diet resulted in a decrease (p < 0.05) in BW, ADG, ADFI and EPEF by 6.4, 6.3, 5.9 and 7.1%, respectively, and an increase in (p = 0.02) cFCR by 2.0%. The tibia dry matter and tibia ash content of these birds were also reduced (p < 0.001) by 3.8 and 4.0% points, respectively. PHY diets improved (p < 0.05) BW, ADG, ADFI, EPEF and cFCR by 8.0, 8.3, 7.3, 10.6 and 2.8%, respectively. Phytase addition at 500 FTU/kg diet also increased (p < 0.001) the tibia dry matter and tibia ash content by 3.5 and 4.2% points, respectively. The pcd of P was improved (p < 0.001) by 11.1 and 11.3% points, in comparison with NC and PC diets, respectively, when phytase was added. These performance parameters and tibia mineralization obtained with a diet supplemented with phytase were comparable to or better than the PC diet. The results demonstrated that avP and Ca could be lowered similarly by 0.15% points in broilers diets by using the new bacterial 6-phytase at 500 FTU/kg diet. Full article

Chlorella vulgaris has been recognized as an interesting alternative feeding source since it contains a good amount of high-quality protein. However, the presence of a recalcitrant cell wall strongly affects the nutrients’ digestibility, bioaccessibility, and bioavailability. The present study aimed to determine the influence of different pre-treatments (bead milling, extrusion, freeze-drying, heating, microwave, and sonication) on C. vulgaris’ protein solubility. For total protein content and solubility, the Bradford method and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) quantification were used, respectively, and protein degradation was assessed by SDS-PAGE through quantification of protein fractions (26 kDa, 32–40 kDa, 66–96 kDa, and others). The o-phthaldialdehyde assay was used for peptide formation. While there were no statistically significant differences for total soluble protein measurements in the supernatant fractions, the results showed an increase in larger proteins following bead milling and microwave pre-treatments, and sonication led to higher fractions of the remaining protein (mostly of low molecular weight). Nevertheless, extrusion significantly increased the release of peptides in the soluble fractions, and, considering industrial applicability, this method may be a better choice for improving C. vulgaris protein bioaccessibility in monogastric diets. Full article

The present study aimed to evaluate the effects of SOD (superoxide dismutase)-rich melon feed supplement on some performance parameters, serum biochemical and antioxidant indexes, and meat quality characteristics of weaned Tuj lambs. An independent measures design (between groups) was used to determine these effects of treatment. After one week of the adaptation period, twenty-four weaned lambs at the age of 60 ± 5.0 days with a body weight of 23.14 ± 0.5 kg were divided into two groups, i.e., the control group (CON) fed basal diet and experimental group (EXP) fed with basal diet + SOD-rich melon (n = 12 per group). The results revealed a decrement in the (p < 0.05) feed efficiency ratio (5.88 ± 0.40 vs. 6.59 ± 0.86 kg weight gain/kg feed) and higher carcass yield (61.76 ± 0.80 vs. 60.11 ± 1.07%) in the EXP group as compared to the CON group. Additionally, the EXP group showed a significant increase (p < 0.05) in serum glucose and high-density lipoprotein levels, while there was a reduction in cholesterol, triglyceride, and low-density lipoprotein levels when compared to the CON group. The serum malondialdehyde was lowered (5.53 ± 0.47 vs. 5.98 ± 0.79 mmol/L) significantly (p < 0.05), while glutathione concentration was higher (p < 0.05) in the EXP group (17.82 ± 1.51 mmol/L) when compared to the CON group (16.54 ± 1.59 mmol/L). The cooking loss was also significantly (p < 0.05) lower in the EXP group when compared to the CON group. In conclusion, the results indicate that SOD-rich melon supplement (30 g/ton of the concentrate feed) can considerably improve carcass yield, some serum biochemical parameters, and meat quality characteristics in Tuj lambs. Thus, the supplementation of lamb diets with a SOD-rich melon additive may be used as an effective nutritional approach to improve their performance and health. Full article

Arthrospira platensis has emerged as a novel protein feed source since it contains high protein level and quality. However, this microalga presents a recalcitrant cell wall and its main proteins form protein-pigment complexes attached to the thylakoid membrane. The objective of the present study was to evaluate the influence of mechanical/physical pretreatments (bead milling, extrusion, freeze-drying, heating, microwave and sonication) on A. platensis protein solubility. Total protein content and solubility were assessed by Bradford method and SDS-PAGE quantification. Protein degradation was assessed through quantification of protein fractions (18–26 kDa, 40–48 kDa and others) in SDS-PAGE gels. Peptide formation was evaluated using the o-phthaldialdehyde assay. The results showed a decrease in total protein content in the supernatant with extrusion (0.07 to 1.42 mg/mL) and microwave pretreatments, and in the pellet with extrusion. Therefore, extrusion, followed by microwave, was the most effective pretreatment for A. platensis proteins denaturation and solubility. It is suggested that the extrusion process cause an irreversible denaturation and aggregation of the major microalga proteins (c-phycocyanin and allophycocyanin), with a strong decrease in their solubility. Therefore, extrusion could increase the bioaccessibility of A. platensis proteins and enable the incorporation of this microalga at higher levels in monogastric diets. Full article

Arthrospira platensis contains high protein content and quality, which makes it a promising feed source for livestock animals. However, this microalga presents a recalcitrant peptidoglycan cell wall, and its main proteins form protein-pigment complexes attached to the algal thylakoid membrane. The purpose of the present study was to evaluate the effect of mechanical/physical pretreatments (bead milling, extrusion, freeze-drying, heating, microwave and sonication) combined with commercial enzymes (trypsin or pancreatin) on the degradation of A. platensis proteins. Protein degradation was assessed through the quantification of total protein and protein fractions (18–26 kDa, 40–48 kDa and others) on SDS-PAGE gels and the evaluation of the coefficient of protein degradation (CPD). The results showed that no significant differences were found among treatments for CPD values, except for an increase related to 18–26 kDa protein (phycocyanin subunits) with extrusion combined with pancreatin. In addition, extrusion and microwave caused a decrease of total protein in algal supernatant probably due to a denaturation/aggregation and reduction of solubility. Overall, extrusion is a promising pretreatment for A. platensis cell wall disruption and protein bioaccessibility. Further studies could elucidate how the effect of extrusion on protein solubility affects the activity of peptidases on protein degradation. Full article

Feed enzymes have been extensively used in livestock diets to enhance nutrient digestion and promote their growth performance. Indeed, recent research has indicated that feed enzymes, notably phytase, protease, and xylanase, function as catalysts, facilitating the breakdown of phytic acid, proteins, and β-1,4-xylan bonds and offering prospective advantages linked to the intestinal well-being and microbiota of young pigs and chickens. Various feed enzymes are currently being added to the diets of swine and broiler chickens. The potential enzymes used in the feed industry include cellulase, β-mannanase, β-glucanases, xylanases, phytases, proteases, lipases, and galactosidases. Though significant research has been conducted on phytase, protease, and xylanase, consistent findings, particularly in terms of improving nutrient digestibility and promoting growth performance of monogastric animals, are still limited. Also, the outcome of recent studies raises the question whether phytase and xylanase could play functional roles beyond increasing nutrient digestibility and intestinal health, such as positively modulating the intestinal microbiota and reducing environmental problems. Therefore, in this review we aimed to address the functional roles of exogenous enzyme activities in monogastric animal diets. Also, we sought to explore the advantages of these enzymes in enhancing the nutritional value of both alternative and conventional feedstuffs. Full article