Feed Conversion Research Articles

Modeling the effects of heat stress on production and enteric methane emission in high-yielding dairy herds.

Given global warming and the growing dairy population, heat stress in dairy herds is of increasing concern. During heat stress, dairy cows suffer from compromised productivity and animal welfare in terms of reduced feed intake and milk production, decreased reproductive performance, and generally increased risk of health problems. These effects and their interactions are complex and are usually quantified separately, and thereby a comprehensive understanding of the herd-level performance is missing. Moreover, compromised animal welfare and productivity may impact enteric methane (CH4) emission, however, these effects have rarely been investigated. Therefore, by performing herd simulation, this study aimed to model the impact of heat stress on dairy production and enteric CH4 emission by aggregating its effects on milk production, reproduction, and health. Specifically, 10 scenarios (including baseline) were simulated in a conventional, high-yielding Danish herd by incorporating different combinations of effects on milk production, reproduction, and health of heat stress in different exposure durations (1, 2, and 4 mo). Sensitivity analyses were further conducted to account for the effects of different reduction rates in feed efficiency (kg ECM/kg DMI). Results showed that heat stress decreased the herd-level milk yield by up to 8.6% if all effects were combined in a duration of 4 mo, whereas a direct effect on milk yield only decreased herd-level yield by up to 6.9%. Heat stress increased the herd-level enteric CH4 intensity ranging from 0.8 to 6.6% across all 9 scenarios as compared with the baseline scenario. When a reduction in feed efficiency by 19.2% was assumed, the herd-level CH4 intensity increased by up to 4.4% during 2 mo. Overall, our results showed large impacts of heat stress on both dairy production and CH4 emission and suggest the need to implement management mitigation strategies in heat-stressed dairy herds.

Nutritional Value of Black Soldier Fly Larvae Oil in Calf Milk Replacers.

Sustainable alternatives to high environmental input feed ingredients are important to reducing the environmental impact of animal agriculture. Protein and oil extracted from cultivation of black soldier fly (Hermetia illucens) larvae (BSFL) on waste feedstocks such as manure, food waste and plant residues could be a suitable source of nutrients. The oil from BFSL contains large amounts of saturated fatty acids, particularly lauric acid, and may be a more sustainable alternative to palm and coconut oils that are currently used in calf milk replacers in many parts of the world. The objective of this study was to evaluate animal performance in neonatal calves fed calf milk replacers (CMR) containing oil from BSFL. Holstein heifer calves (n = 100) were assigned randomly at birth to receive one of 4 experimental containing 24% CP and 18% fat from a blend of 80/20 palm/coconut oil (B0), 80/20 palm/BSFL oil (B20), 70/30 palm/BSFL oil (B30), or 60/40 palm/BSFL oil (B40). Calves were fed up to 900 g/d of CMR powder reconstituted to 15% solids daily to d 55, then 600 g/d to d 63 and 300 g/d to the end of the trial at d 70. Commercial calf starter, wheat straw, and water were available for ad libitum consumption. Intake, growth, fecal scores, and feed efficiency were monitored and reported weekly. There were no effects of experimental treatments on growth, or feed efficiency. Consumption of CMR during the first 2 weeks of the study were lower when calves were fed B20 (wk 1 and 2) or B30 (wk 2). Calves were generally healthy and there were no indications of feed refusal or maldigestion. Probability of a non-normal fecal event (fecal score > 0) was lower when calves were fed B20 during the first 3 weeks of the study. Oil from BSFL may be an attractive alternative to palm and coconut oil in calf milk replacers.

Forma física da ração, sistemas de alimentação e níveis de energia metabolizável em dietas para frangas semi-pesadas

ABSTRACT: Evaluated different feed forms (FF), (mash or pellets), feeding systems (FS) (ad libitum or controlled) and metabolizable energy levels (ME) (2,900 kcal/kg or 2,750 kcal/kg) in rearing period 1 (7 to 12 weeks) and 2 (13 to 17 weeks). Utilized 400 brown-egg laying pullets a completely randomized design in 2x2x2 factorial arrangement (eight treatments, with five replications). In period 1, feed intake was similar (P > 0,05) between FF and between ME, however pullets fed ad libitum showed 27.5% higher intake than fed with controlled amounts (P < 0,05). Body weight (BW) differed (P < 0.05) in the FS. Feed conversion (FC) was not affected (P > 0.05) by any of the study factors. Flock uniformity was affected (P < 0.05) by FF and by FS, with an interaction between the factors (P < 0.05). The pullets fed the mash feed ad libitum had better uniformity (P < 0.05) than the pullets fed with the controlled mash feed. The pelleted feed caused the worst uniformity. In rearing period 2, feed intake was affected (P < 0.05). That pullets fed mash or pelletized feed ad libitum consumed 8g more (P < 0.05) on average, than those in the controlled FS. In the ad libitum supply, intake was higher (P < 0.05) for the mash feed than for the pelleted feed. BW and FC were not affected by any of the factors (P > 0.05). Uniformity (%) was influenced by the mash or controlled systems (P < 0.05). Between 7 and 17 weeks of age, brown-egg laying pullets need to be fed with a mashed diet in a controlled feeding system, with 2,750 kcal/kg of metabolizable energy.

Tetrastigma hemsleyanum as a feed additive: modulating gut microbiota for enhancing nutritional transport and growth performance in Jinhua yellow chickens.

Tetrastigma hemsleyanum (TH) has attracted much attention for its heat clearing and detoxification effects, but whether it can become an effective feed supplement in chickens remains unclear. Herein, a total of 120 male Jinhua yellow chickens (two-mth-old) were randomly divided into into four groups (CON, TH-L, TH-M, and TH-H) for a 56-day feeding trial to explore its effects on growth performance and underlying mechanism. Results revealed that dietary TH notably increased the average daily growth (ADG), and decreased the average daily feed intake (ADFI) and feed conversion ratio (FCR) in TH-H group during 29-56 days. Meanwhile, dietary TH improved the development of duodenum and notably increased the contents of essential amino acids and flavor amino acids, while the serum oxidation stress index as well as abdominal fat deposition were not affected in Jinhua yellow chickens. Additionally, TH supplementation notably increased gut microbiota richness, then selectively increased the colonization of potential probiotics and the microbial abundance associated to amino acid synthesis and metabolic pathways in duodenum. Furthermore, qPCR analysis results preliminarily verified that dietary TH not only enhanced intestinal amino acids (rBAT and EAAT3) and peptides (PepT1 and APN) transport but also alleviated the inflammation (IL-1β, IL-6 and IFN-γ), thus thereby improved intestinal development and growth performance in Jinhua yellow chickens. These findings demonstrated that TH is a feed additive that can improve growth performance, muscle amino acids composition and intestinal development.

Effects of dietary metabolizable energy and crude protein levels on production performance, meat quality and cecal microbiota of Taihe Silky Fowl during growing period.

This experiment aimed to investigate the effects of dietary metabolizable energy (ME) and crude protein (CP) levels and their interaction on the performance, meat quality, and cecal microbiota of Taihe Silky Fowl (Gallus gallus domesticus Brisson) during the growing period. A total of 2160 55-day-old Taihe Silky Fowl (half male and half female) were randomly divided into 9 groups with 6 replicates per group and 40 chickens per replicate. The fowl were fed with a 3 × 3 factor diet (ME: 11.7 MJ/kg, 12.1 MJ/kg, 12.6 MJ/kg; CP: 17.0%, 18.0%, 19.0%). The results showed as follows: with the increase of dietary ME level, the average daily feed intake (ADFI) and feed conversion ratio (FCR) of Taihe Silky Fowl during the growing period were significantly decreased (P < 0.05), reaching the lowest value in 12.6 MJ/kg group, which were decreased by 5.86% and 8.41% compared with 11.7 MJ/kg group, respectively. The dressing percentage and half-eviscerated yield rate were significantly increased (P < 0.01), with no significant difference between 12.1 and 12.6 MJ/kg groups. Dietary CP level and the interaction between ME and CP had no significant effects on growth performance, slaughter performance, organ index, serum biochemical indexes and meat quality of Taihe Silky Fowl during growing period. The richness and diversity of cecal microbiota decreased gradually with the increase of dietary ME level, and the community structure changed significantly (P < 0.05). High ME diet (12.6 MJ/kg) significantly increased the abundance of Bacteroides (P < 0.05), especially the genus Alistipes, which may indirectly improve nutrient absorption efficiency and overall health status of Taihe Silky Fowl through its metabolites and effects on intestinal microbial community structure, thereby reducing FCR. In conclusion, the optimal production performance and economic benefits can be obtained when the diet ME is 12.6 MJ/kg and CP is 17.0%.

Effects of cage size on the natural behavior, serum parameters, production performance and hypothalamic mRNA expression profiles of laying hens

The objective of this study was to evaluate the effects of cage size on the natural behavior, serum biochemistry, production performance and hypothalamic transcriptome profiles of laying hens. A total of 360 79-week-old hens were selected and randomly assigned to three groups (with five replicates each) with different cage sizes: large cages (LCs), medium cages (MCs), and small cages (SCs). The stocking density remained consistent across all groups throughout the experimental period. Behavioral expression was evaluated through observation of only six birds per group on a weekly basis. Compared to the SC group, the average frequencies of walking, wing-flapping, feather-pecking and drinking significantly increased in the LC and MC groups (P <0.05), whereas the average frequency of stereotypic behavior significantly decreased (P <0.05), indicating that cage size has positive effects on natural behavior. The average daily step count (DSC) was in the order LC > MC > SC (P <0.05), which suggested an improvement in exercise ability in larger cages. The serum levels of MDA, CORT, AST and T-CH were significantly lower in the LC and MC groups than in the SC group (P <0.05), whereas the serum activities of SOD and GSH-Px were significantly greater (P <0.05). Additionally, compared to the SC group, the laying rates were increased by 1.61% and 2.20% (P <0.05), and the feed conversion ratio (FCR) were improved by 1.35% and 2.25%, respectively (P <0.05) in the LC and MC groups, respectively. In total, 437 and 81 differentially expressed genes (DEGs) were identified in the hypothalamus of birds between the LC and SC groups and the MC and SC groups, respectively. A majority of these DEGs were involved primarily in neuroactive ligand‒receptor interactions, focal adhesion and calcium signaling pathways, which are associated with the regulation of behavioral patterns, the stress response and follicular development. Our results suggest that an appropriate increase in cage size is beneficial to the natural behavior expression, health status and production performance of laying hens.

Enhancing Broiler Growth and Carcass Quality: Impact of Diets Enriched with Moringa oleifera Leaf Powder Conjugated with Zinc Nanoparticles

This study evaluated the effects of Moringa oleifera leaf powder extract stabilized with zinc nanoparticles (ZnNPs-MLPE) as a natural growth promoter in broiler diets. Randomly assigned 264 one-day-old Ross 308 chicks to four different feeding treatments, with each group being subdivided into six replicates, each comprising 11 unsexed chicks. The control group was fed a basic diet without additives, while the experimental groups were supplemented with 1.0, 2.0, or 3.0 cm³ of ZnNPs-MLPE/L of diet. The findings demonstrated that 2.0 and 3.0 cm³/L ZnNPs-MLPE supplementation significantly enhanced live body weight (LBW) and weight gain (BWG). Feed intake (FI) and feed conversion ratio (FCR) did not show significant differences between the treated groups and the control, indicating that the additive did not negatively affect feed efficiency. However, an increase in abdominal fat was noted in the ZnNPs-MLPE treatments relative to the control. Blood analysis revealed that the ZnNPs-MLPE groups had significantly lower levels of "total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), and alanine transaminase (ALT) compared to the control group. In contrast, total protein (TP), albumin, and the albumin/globulin (A/G) ratio" were higher in the ZnNPs-MLPE groups. Immunoglobulins IgY and IgM, as well as superoxide dismutase (SOD) levels, were elevated. Malondialdehyde (MDA) levels were reduced, indicating improved antioxidant capacity and immune function in the ZnNPs-MLPE-treated groups. In conclusion, supplementation with ZnNPs-MLPE at 2.0 and 3.0 cm³/L positively impacted broiler growth efficiency, antioxidant capacity, and immunological functionality. These findings support the potential of ZnNPs-MLPE as an effective natural growth enhancer for producing healthier poultry products.

The hidden drivers: Unraveling the impact of density, moisture, and scale on Hermetia illucens rearing.

The black soldier fly (Hermetia illucens) is a saprophagous insect known for bioconverting organic waste, potentially offering environmental benefits, such as contributing to waste reduction and nutrient cycling. The performance of larvae varies significantly with factors substrate moisture, larval density, and scale of production. Three experiments were conducted using a mix of spent mushroom substrate (SMS) and chicken feed (CF). In the first experiment, 250 larvae were reared on 100 g dry matter (DM) feed at moisture levels of 65-75%. Results showed that the average individual larval weight, total biomass, and feed conversion ratio (FCR) improved with increased moisture. In the second experiment, 300 and 350 larvae/box were tested at 70% and 75% moisture. The highest average individual larval fresh weight (158.6 mg) was observed at 70% moisture with 250 larvae, while the highest biomass was achieved at 75% moisture with 300 larvae. Finally, different scales (10-2,500 g feed with 25-6,500 larvae) were tested with a similar feeding rate. The highest individual larval weight was recorded at the 100 g scale, with no clear correlation between weight and scale. However, the 50 g scale achieved the highest substrate reduction (33.2%). Overall, this study underscores the need to adjust moisture, density, and scale to nutrient conversion efficiency when using SMS, CF or other diets. The optimal results for the SMS feed mix were observed at 75% substrate moisture, 250 larvae per 100 g DM, and at approximately 2 larvae per cm2.

Influence of Multistrain Probiotics on Growth, Hematology, Gut and Liver Morphometry, and GH and IGFs Genes Expression in Rohu (Labeo Rohita) Fry

Probiotic is regarded as an effective feed additive to increase the growth, feeding efficiency, survivability, and overall productivity of fishes in aquaculture. The following study was intended to examine the effects of multistrain probiotics on growth, blood indices, histomorphometry of gastrointestinal tract and liver, and growth hormone (GH) and insulin‐like growth factors (IGFs) genes expression in rohu Labeo rohita. Probiotic containing Bacillus subtilis, B. thuringiencis, Lactobacillus plantarum, and L. buchneri was inoculated in water and three different doses, that is, 0 mL/L (control), 0.5 mL/L (lower dose, T1), and 1.0 mL/L (higher dose, T2) were used in this study. Each treatment had three replicates and fishes were reared in aquarium for 60 days. Results revealed that substantially higher weight gain (WG) and specific growth rate (SGR) along with least apparent feed conversion ratio (AFC) were documented in probiotic treated fish which was significantly different than that of control, however, higher dose (1.0 mL/L) showed best performance. Blood–biochemical indices such as red blood cell (RBC), white blood cell (WBC), hemoglobin (Hb), and glucose (Glu) level were observed statistically higher in probiotic additive culture water. Moreover, the inoculation of multispecies probiotic positively altered the intestinal histometry. Besides, immune response features of intestine were observed significantly higher in probiotic treated fish. The nucleus shape and distances between liver tissues (DLTs) were also improved with the upward doses of probiotic application. The mRNAs levels of GH in the pituitary and IGF‐1 and IGF‐2 in the liver were significantly higher in probiotic treated fish. In a nutshell, this study suggested that the inclusion of multistrain probiotics showed promising improvement in growth performance and feed conversion efficiency; additionally, uplifted the intestinal structure integrity, liver morphology, and GH and IGFs genes expression in rohu.

Transforming Feather Meal Into a High-Performance Feed for Broilers.

The poultry industry faces challenges with the high cost and environmental impact of Soybean meal. Feather meal, a byproduct with low digestibility due to its keratin content, is a potential alternative. Recent biotechnological advances, including enzymatic and bacterial hydrolysis, have enhanced its digestibility and nutritional value. This study aimed to evaluate and compare the efficacy of three different feather meal processing methods as partial replacements for soybean meal in broiler diets. The methods assessed included hydrolyzed feather meal treated with Streptomyces bacteria, commercial enzyme-treated feather meal, and boiled feather meal. Their effects on performance and nutrient digestibility were evaluated in Ross 308 male broiler chickens. The study involved 525 Ross 308 male broiler chickens were allocated to seven dietary treatments, which included a control diet and varying combinations of feather meal and soybean meal. Streptomyces sp. MSM5 was shown to effectively produce keratinase, enhancing the amino acid content of the feather meal. Birds fed diets containing 33% and 67% boiled feather meal exhibited significantly reduced body weight gain (BWG) and increased feed conversion ratio (FCR) compared to the control group (p < 0.05). In contrast, birds fed diets with 33% hydrolyzed feather meal, treated with either enzymes or bacteria, showed similar BWG and FCR to those on the control diet. However, diets with 67% hydrolyzed feather meal led to significant reductions in performance (p < 0.05). Additionally, diets containing 33% and 67% boiled feather meal, as well as 67% hydrolyzed feather meal, resulted in significantly lower carcass percentage, breast muscle percentage, thigh muscle percentage, overall dry matter digestibility, and protein digestibility (p < 0.05). The results indicate that substituting as much as 33% of soybean meal with processed feather meal, particularly when treated with enzymes or bacteria, does not negatively impact broiler performance. Furthermore, the results underscore the potential of biotechnological treatments, such as bacterial keratin hydrolysis, to enhance the nutritional value of feather meal, transforming it into a high-quality, sustainable protein source for the poultry industry.

Effect of Daucus carota subsp. sativus on pigmentation and profitability of Cobb 500 broiler chicken

Background: The quality of chicken meat, essential for consumer satisfaction, is influenced by skin pigmentation. The lack of carotenoids in conventional diets motivates the search for cost-effective alternatives to enhance these aspects in poultry production. Objective: This study assessed the impact of partially replacing commercial balanced feed with different levels of carrot flour (Daucus carota subsp. sativus) on productive parameters and the pigmentation of broiler chickens. Methods: 64 Cobb 500 birds were randomly assigned to four experimental diets, each with eight replicates of two birds. The control group (T1) received a standard diet, while experimental groups received a diet with 10% (T2), 15% (T3), and 20% (T4) replacement with carrot flour. Variables such as feed consumption, weight gain, feed conversion, mortality, skin pigmentation, and profitability were evaluated. Results: Treatments with 15% and 20% carrot flour showed higher feed consumption. Birds in experimental groups exhibited higher weight gain and improved feed conversion, with no reported mortality. Regarding pigmentation, carrot flour influenced skin color as its concentration in the diet increased. In terms of profitability, the 15% replacement treatment stood out by generating higher income and a superior cost-benefit ratio. Conclusion: Orange cultivar carrot flour can be a viable dietary source of natural pigment for broiler chickens. It may also be beneficial in promoting weight gain and reducing mortality, translating into economic advantages.

EFFECT OF DIFFERENT STOCKING DENSITIES IN BIOFLOC-BASED CATFISH (Clarias batrachus) CULTIVATION ON WATER QUALITY AND PRODUCTION PERFORMANCE

Biofloc Technology (BFT) is an innovation in fish farming aimed at improving feed efficiency and water quality by assisting heterotrophic bacteria. This study aims to improve water quality (ammonia, nitrite, nitrate, sulfate, phosphate) and fish production performance (average daily growth/ADG, average body weight/ABW, production, specific growth rate/SGR, feed conversion ratio/FCR, survival rate/SR). Catfish with an initial weight of 18.7±0.1 g and length of 11.48±0.02 cm were reared for 40 days with feed amounting to 2-4% of body weight. Parameters were measured every 10 days and analyzed using a Completely Randomized Design (CRD) with 4 treatments (A: without biofloc; B, C, D: using biofloc with densities of 100, 125, and 175 fish/m³). The results showed that biofloc improved water quality (ammonia 0.2165-0.5322 mg/L, nitrite 0.0044-0.0616 mg/L, nitrate 0.2863-19.6422 mg/L, phosphate 0.0169-0.8865 mg/L, and sulfate 2.6097-34.0627 mg/L), and enhanced fish production performance (ADG 1.625-3.85 g/fish/day, ABW 65-154 g/fish, production 5.251-16.176 kg, SGR 3.633-4.642%, FCR 0.849-1.007, and SR 65-89%). Biofloc technology effectively supports catfish survival up to a density of 175 fish/m³, demonstrating that BFT is a cost-effective, sustainable, and environmentally friendly aquaculture technology.

Malic acid- heat- treatment of proteins reduces methane and nitrogen emissions with improvement in growth, feed efficiency and nutrient utilization in Murrah buffalo (Bubalus bubalis)

Malic acid- heat- treatment of proteins reduces methane and nitrogen emissions with improvement in growth, feed efficiency and nutrient utilization in Murrah buffalo (Bubalus bubalis)

Diet supplementation with a mixture of essential oils: Effects on enteric methane emissions, apparent total-tract nutrient digestibility, nitrogen utilization, and lactational performance.

This study examined the effects of supplementing dairy cows with a mixture of essential oils on enteric CH4 emissions, apparent total-tract nutrient digestibility, N utilization, and lactational performance (production, components and efficiency). Thirty-two multiparous lactating Holstein cows were used in a randomized complete block design. Cows averaged (mean ± SD) 95 ± 15.4 DIM, 47.7 ± 4.51 kg milk yield, and 698 ± 68.2 kg BW, at the start of the experiment. The experiment consisted of a 3-wk pretreatment period (i.e., covariate), followed by a 3-wk adaptation to the experimental treatments, and a 10-wk period for data and sample collection. At the beginning of the study, milk yield and DIM data were used to block the cows into 16 blocks of 2 cows each. Subsequently, the blocks were adjusted based on milk yield and enteric CH4 emission data collected during the pretreatment period. Within each block, cows were assigned to 1 of 2 dietary treatments: (1) a basal diet supplemented with a placebo (control, no additive), or (2) a basal diet with the essential oil supplement (Agolin, 1 g/cow/d). The basal diet (i.e., total mixed ration) was composed of 69.3% forage (corn and alfalfa silage and grass hay) and 30.7% concentrate, on a dry matter (DM) basis, while the essential oil mixture consisted mainly of coriander seed oil, eugenol, geraniol and geranyl acetate. Twice daily, the essential oil supplement was thoroughly mixed with 50 g of a commercial protein supplement (i.e., carrier) and 500 g of the TMR and this premix (i.e., 550 g/meal) was offered to the cow before the basal diet. No interactions between the essential oil supplement and the sampling week were observed for any of the response variables. Dry matter intake, apparent total-tract nutrient digestibility and N balance were unaffected by feeding the essential oil supplement. Yields of milk, 4% FCM, and ECM were not modified by the experimental treatment. Neither feed efficiency (kg milk/kg DMI, kg 4% FCM/kg DMI, kg ECM/kg DMI) nor dietary N use efficiency in milk N secretion (i.e., g milk N/ g N intake) were affected by essential oil supplementation. Body weight change and BCS did not differ between cows fed the essential oil supplement versus cows fed the control. Daily enteric CH4 emissions, CH4 yield, and CH4 intensity averaged 498 g/d, 18.4 g/kg of DMI, and 11.0 g/kg of ECM, respectively, and were unchanged by essential oil supplementation. We conclude that supplementing cows fed a high-forage diet with 1 g/d of this essential oil mixture did not positively affect lactational performance, nutrient digestibility, and N utilization, or reduce enteric CH4 (emissions, yield, and intensity). More research is needed to identify the optimal dose of this essential oil mixture and elucidate how it may interact with the basal diet to improve the mixture's efficacy.

Inclusion of dried citrus pulp in the barley-based supplementary concentrate to beef cattle offered grass silage: Intake, digestibility, feed efficiency, and carcass and meat quality traits

Inclusion of dried citrus pulp in the barley-based supplementary concentrate to beef cattle offered grass silage: Intake, digestibility, feed efficiency, and carcass and meat quality traits

Ziziphus nummularia and Acacia nilotica leaves based polyphenols rich diet modulates fatty acid profile and keeping quality of lamb meat

The polyphenols, due to their chemical characteristics, are known to alter microbial populations, impart antioxidant properties, and bind proteins. Accordingly, the present study was carried out to study the potential of plant polyphenol-rich diets in modulating the fatty acids (FAs) profiles and keeping quality of lamb meat. For this, thirty Avishan lambs (10 weeks old, 14.0 ± 0.2kg) were randomly distributed into three groups: control (T1) on a complete feed block containing Vigna sinensis hay, T2 on CFB containing Acacia nilotica, and T3 on CFB containing Ziziphus nummularia leaves. The CFB in T1 had a negligible quantity of polyphenols, whereas T2 was rich in hydrolysable tannins, and T3 was rich in condensed tannins. The feeding trial was carried out for 12 weeks. A lower intake of nutrients (per kg BW0.75) was recorded in T2 compared to T1 and T3, while feed efficiency was similar across all treatments. Five lambs from each group were slaughtered at the end of the feeding trial for studying carcass attributes. T1 and T3 recorded higher (P = 0.003) weight gain, whereas T2 and T3 had higher dressing percentages and loin-eye areas. The FAs profile of Longissimus thoracis muscle in T2 and T3 showed a positive shift (decreased saturated and trans-FAs and increased ω-3, ω-6, and polyunsaturated FAs) with healthier atherogenicity and thrombogenicity indices. The carcasses of T2 and T3 showed improved keeping quality following 14 days of refrigerated (4°C) storage, as evidenced by lower malondialdehyde values. Between the two sources, the condensed tannin-rich Z. nummularia showed superiority over the hydrolysable tannin-rich A. nilotica in modulating FA biohydrogenation and preserving keeping quality.

Feed efficiency and resilience in dairy ewes subjected to a nutritional challenge.

It is currently uncertain how selection of more efficient animals might impact other traits such as resilience (which, in this context, is defined as the ability of an animal to sustain or revert quickly to its previous production level and health status after a disturbance), especially in small ruminants. However, improving, or at least maintaining, resilience is of utmost importance to ensure livestock production in the face of external perturbances, which are expected to become more prevalent in the near future due to climate change and global instability. This study was conducted to investigate whether a nutritional challenge consisting of animals receiving only 70% of their voluntary feed intake (DMI) for 26 d, might differentially affect the response of high- and low-feed efficiency (FE) sheep. To meet this aim, residual feed intake (RFI), as a proxy of FE, was calculated in 40 lactating ewes fed a total mixed ration ad libitum. Using the RFI values, the ewes with the highest (H-FE; n = 8) and the lowest (L-FE; n = 8) FE were selected and subjected to the nutritional challenge. After the feed restriction, all sheep were again fed ad libitum for a further 25 d. Temporal patterns of variation in animal performance, ruminal fermentation and blood and milk metabolites in response to, and recovery from, the underfeeding were examined in H-FE versus L-FE. More efficient ewes (H-FE) tended to eat less than less efficient ewes (L-FE) for the same level of production. Linear regressions for DMI and milk yield data showed that time-series response to the challenge was comparable in L-FE and H-FE. Despite temporal changes due to underfeeding, both FE divergent groups displayed a similar response to, and recovery from, the challenge with no significant differences in the temporal patterns of variation of the parameters analyzed, except for a tendency to higher plasma glucose in the L-FE ewes. These results challenge the general hypothesis that more efficient animals would be less resilient, but further research is still needed on the relationship and possible trade-offs between high efficiency and resilience.

Effects of Amino Acid Supplementation on the Growth Performance of Broiler Chicks Challenged With Coccidiosis: A Meta-Analysis.

This meta-analysis aimed to evaluate the effects of amino acid supplementation on the growth performance of broiler chicks challenged with coccidiosis. Data were collected on authorship, publication year, study sample characteristics and outcomes of interest related to growth performance. Effect sizes were calculated for both overall effects and the individual effects of each amino acid. The effects of moderator factors, such as supplementation levels and duration, were also assessed, and bias was calculated. Works were obtained from PubMed, Elsevier, ScienceDirect, Wiley, Springer Link and Scopus databases, with the help of search engines like Google Scholar and ResearchGate, covering the period from 2013 to 2023. A random-effects model was used. Thirteen works were included in the current analysis, examining the effects of arginine (n=4), methionine (n=6), threonine (n=3) and glutamine (n=3). Amino acid supplementation [0.326, CI 95% (0.297-0.355); p=0.000], arginine [0.430, CI 95% (0.293-0.568); p=0.000] and threonine [0.793, CI 95% (0.193-1.38); p=0.009] significantly increased body weight. Amino acid supplementation [0.052, CI 95% (0.022-0.081); p=0.000] and arginine [0.317, CI 95% (0.049-0.585); p=0.000] also significantly increased feed intake. Higher levels of amino acids (≥1.50%) and longer supplementation periods (≥15 days) significantly increased body weight and feed intake, while reducing the feed conversion ratio. Funnel plots, fail-safe N and Egger tests showed no evidence of bias. In conclusion, arginine supplementation has the potential to increase body weight and feed intake in poultry challenged with coccidiosis. Higher doses of amino acids and longer supplementation periods are recommended in such cases.

Intestinal mucosal morphology and microbial flora population in Arianstrain broilers fed with Spirulina platensis supplemented drinking water

The aim of this study was to evaluate the impacts of different levels of Spirulina platensis supplementation on the mucosal morphology of the intestine of broiler chickens. Spirulina, a single-celled algae, has been recently categorized as a filamentous, gram-negative Cyanobacterium, which offers significant benefits in broiler nutrition by improving growth performance through its high protein content, enhancing immune function, boosting feed conversion efficiency, and supporting gut health. A total of 375 one-day-old male Arian broilers were included in a 6-week trial. The chicks were randomly assigned to five treatment groups, each with five replicates of 15 birds, received different concentrations of Spirulina in their drinking water: Group A (5 g/L), Group B (2.5 g/L), and Group C (1 g/L), while the control groups received either no additive or an antibiotic (Fosbac Biotic®). This study examined the effects of dietary Spirulina platensis supplementation on cecal, the height of intestinal villi, and the depth of crypts in Arian strain broiler chickens examined. The results indicated Spirulina increased villus height, reduced crypt depth, and improved the villus-to-crypt ratio in the duodenum jejunum and ileum, suggesting enhanced nutrient absorption. Moreover, Spirulina supplementation increased beneficial bacteria (lactobacilli) and reduced harmful bacteria (coliforms), improving overall gut health and reducing digestive problems. Further research is advised to explore the economic benefits of using Spirulina in the poultry industry.

Comparative Study of Duodenal Histology in Three Lamb Breeds Fed Two Different Rations.

Ration composition may significantly impact the nutrient absorption, duodenal parameters, intestinal health and feed efficiency of animals. The objective of this study was to analyse the impact of concentrate- and forage-based diets on essential morphological parameters of the duodenum, including villus height, villus width, crypt depth and goblet cell density, in three different lamb breeds. Forty-five lambs, aged between 2.5 and 3 months and with an average weight of around 20kg, were selected. The lambs were fattened on two different diets consisting of pelleted concentrate and alfalfa hay in predetermined ratios: 70% concentrate + 30% forage and 70% forage + 30% concentrate. When the lambs reached 40kg, they were slaughtered, and duodenum tissue samples were collected for analysis. Histological characteristics were assessed by evaluating duodenal tissues from lambs of three breeds-Akkaraman, Karayaka and Herik-across the two dietary groups within each breed, and the essential parameters of the villus were measured. Akkaraman lambs exhibited lower goblet cell count and villus height (VH) as compared to Karayaka and Herik lambs. Goblet cell count and VH were higher in concentrate-fed lambs, except for Karayaka lambs. However, goblet cell density was similar across Akkaraman, Karayaka and Herik lambs. Herik lambs had higher VH, villus width (VW) and villus surface area as compared to Akkaraman and Karayaka. Villus parameters were generally lower in concentrate-fed lambs, except for Herik lambs. Overall, the study suggests that altering the roughage-concentrate ratio did not significantly affect duodenal mucosa parameters. However, differences were observed across genotypes, particularly in Herik lambs, indicating potential associations between duodenal parameters and genotype.