Growth Performance, Intestinal Histomorphology, Blood Hematology and Serum Metabolites of Broilers Chickens Fed Diet Supplemented with Graded Levels of Acetic Acid

Investigation of dietary exogenous protease and humic substance on growth, disease resistance to Flavobacterium covae and immune responses in juvenile channel catfish (Ictalurus punctatus)

Many bacterial pathogens impact the US catfish industry, and disease control can be challenging for producers. Columnaris disease in channel catfish, Ictalurus punctatus, is primarily caused by Flavobacterium covae (formerly F. columnare). Immunostimulants may enhance nonspecific immune responses and offer an alternative to antibiotic treatments in catfish. Furthermore, dietary protein sources and inclusions are also essential to fish health and nutrition and may enhance overall fish performance in pond culture. The current project evaluated two immunostimulants: a protease complex (PC) and a humic substance (HS) derived from a reed-sedge peat product. A 60-day trial examined the effects of five diets on growth performance, immune response and resistance to experimental F. covae infection in channel catfish. Diets included a high-quality fishmeal diet (32%; CF32), a high-protein soy-based diet (32%; C32), a low-protein soy-based diet (28%; C28; predominately used in industry), a low-protein soy diet supplemented with C28 + PC at 175 g metric ton^-1 and C28 + HS in a low-protein diet at 23 g metric ton^-1 . Following feeding for 60 d, juvenile channel catfish were sampled for growth performance and baseline health indicators (n = 3; body mucus, blood for sera, kidney and spleen). A subset of fish was then subjected to an immersion-based in vivo challenge trial with F. covae (ALG-00-530; 10⁶  CFU mL^-1 exposure). At 60d post-initiation, there were no dietary differences in the relative growth rate (p = .063) or thermal growth coefficient (p = .055), but the 32% diets generally appeared to perform best. Post-challenge, the C32 group's mortality was higher than the C28 + PC (p = .006) and C28 + HS diets (p = .005). Although not significant, the C28 and CF32 groups also demonstrated higher mortality compared to both PC and HS diets. Sera lysozyme concentration was found to increase following pathogen challenge (p < .001) and in comparison with mock-challenged catfish (p < .001). Elevated expression levels of proinflammatory cytokines (il-1β, il-8, tnf-α and tgf-β) were observed at trial midpoint and post-infection when compared to 60d. The C28 treatment was found to have lower tnf-α expression than the C28 + PC (p = .042) and C28 + HS (p = .042) groups following exposure to F. covae. These challenge data suggest that the immunostimulants (PC and HS) in plant-based protein may be beneficial in protecting against F. covae when offered in low-protein channel catfish diets.

Does the use of lactic acid as an antibiotic substitute in broiler diets affect growth, carcass traits, blood indices and intestinal microbiota?

The objective of the current study was to determine the impact of lactic acid (LAC) as an antibiotic alternative in broiler diets on growth performance, carcass traits, blood indices and intestinal microbial load. A total of 300 broiler chicks one day old (Ross 208) were allotted to five experimental groups in a complete randomized design experiment. Each group was subdivided into six replicates, each of ten unsexed chicks. The treatments were as follows: NC: negative control (basal diet); PC: positive control (basal diet + 0.5 g Colistin® antibiotic/kg diet); LAC2, LAC4, and LAC6: basal diet + 2, 4, and 6 cm³ lactic acid/kg diet, respectively. Results showed no significant effects of dietary treatments (antibiotic or lactic acid) on growth performance traits (body weight, BW; daily body weight gain, DBWG; feed intake, FI and feed conversion ratio, FCR) and carcass characteristics except for Thigh %. All blood biochemical traits were affected (p > 0.01) by dietary treatments. The highest values of blood total protein and albumin were found in birds of LAC2 group. Adding graded doses of LAC to broiler diets inhibited the activity of liver enzymes and reduced the concentration of blood urea. The positive effect of LAC supplementation excelled that of antibiotics regarding the antioxidant status parameters. The lowest pathogenic bacteria (E. coli and Salmonella) were recorded by LAC4 and LAC6 groups. It could be concluded that dietary supplementation of lactic acid did not significantly affect most growth performance traits. But its use could have beneficial impacts on blood parameters, oxidative status and intestinal microbial counts. Based on our results, the highest level (6 cm³ LAC/kg diet) is the recommended level for the best results.

Exploration of Zingiber officinale effects on growth performance, immunity and gut morphology in broilers

The current study aimed to determine the effects of different levels of Zingiber officinale as a herbal feed additive on growth performance, carcass characteristic, serum biochemistry, total bacterial count (TBC), gut morphology, and immunological parameters of broilers. A total of 1500, day-old broiler chicks (Hubbard) were equally accredited to five treatment groups, each with six replicates (50 birds/replicate). Five experimental diets were prepared using basal diet i.e. with antibiotics positive control (PC), 3 g/kg ginger (group A), 6 g/kg ginger (group B), 9 g/kg ginger (group C) and without antibiotics negative control (NC). Group A and C showed significantly (p<0.05) higher feed intake (FI) as compared to other groups. Group C showed significantly (p<0.05) lower Total bacterial count (TBC) followed by group B as compared to NC. Carcass characteristics showed non-significant effects among different treatments. Mean villi length and width were significantly (p <0.05) higher in all ginger supplemented groups as compared to the control groups. Blood serum parameters including cholesterol, triglycerides, and low-density lipoproteins (LDL) were significantly (p<0.05) lower in groups B and C in comparison with the control groups. Whereas high-density lipoproteins (HDL) was significantly higher in group B as compared to the others. In conclusion, ginger supplementation @0.6% in the basal diet significantly improved growth performance and gut morphometry of broilers. It also showed a positive impact on cholesterol, triglycerides and gut microbes. Therefore, ginger could be a better substitute for antibiotic growth promoters.

The Antioxidative Impact of Dietary Vinegar and Rocket Salad on the Productivity, Serum Oxidation System, and Duodenal Histology of Chickens

The purpose of the study was to investigate the ameliorative effect of dietary rocket salad and apple cider vinegar on the oxidative stress (OS) status of broilers. Specifically, 720 Ross 308 chicks were divided into six groups: negative and positive controls (NC and PC with and without additives, Vi1 and V12 experimental groups fed with diets mixed with 5 and 10 mL of vinegar/kg, and Ro1 and Ro2 groups fed with diets mixed with 2 and 3 g of rocket salad/kg, respectively). The experimental groups Vi1 and Vi2 were fed with feed mixture moisturized with 5 and 10 mL of vinegar/kg, and Ro1 and Ro2 were fed with 2 and 3 g of rocket salad/kg, respectively. The birds' productivity, oxidative serum parameters, and morphometric indices of the gastrointestinal tract were registered at 6 weeks of rearing. The vinegar or rocket salad additive had powerful potentials to significantly suppress (p ≤ 0.05) OS through improving the birds' survivability, body weight gain, feed conversion ratio, and carcass yield. The highest villus height and villus height/crypt depth ratio of the duodenum were achieved by Vi2, Ro1-2, and NC (p ≤ 0.05). The villus surface area and muscular layer thickness were smallest in the PC, while they did not differ significantly in other groups (p > 0.05). Similar relationships were found in serum superoxide dismutase, glutathione peroxidase, hydroperoxide, and malondialdehyde; however, higher doses of both additives were more effective. It seems that liquid vinegar and rocket salad could have beneficial influences on the antioxidant status of birds.

Dietary citric acid enhances growth performance, nutrient digestibility, intestinal microbiota, antioxidant status, and immunity of Japanese quails

A total of 300 un-sexed Japanese quail chicks (1-wk-old) were randomly allotted to 5 experimental groups to study the effect of citric acid (CA) on performance development, carcass estimates, blood measurements, antioxidant and immune measurements, digestive enzymes, and cecum microbiology traits of growing Japanese quail. The chicks were fed a basal diet supplemented with CA (5, 10, 15, and 20 g/kg in diet) had significantly (P < 0.05) greater live body weights at 3 and 5 wk of age and increased weight gain across all experimental periods (1–3, 3–5 and 1–5 wks of age) compared to the control group. No significant difference was found in any of the measured carcass traits. The digestion coefficients of crude protein, ether extract, crude fiber, and nitrogen free extract as well as metabolizable energy significantly improved (P < 0.05) in all treatment groups compared to the control. CA supplementation from 10 to 20 g/kg had increased digestive enzyme activities (amylase and lipase). All treatment groups had higher (P < 0.05) albumin and globulin concentrations than the control group. A significant (P < 0.05) decrease in phosphorus (P) concentrations in the plasma was observed in all treatment groups. The IgG levels were greater (P < 0.05) in the 5 or 10 g/kg groups than the control group. Chicks fed CA at different levels had significantly decreased caecal content of TBC, coliform, E. coli, and Salmonella. We concluded that the inclusion of CA (especially 10 g/kg diet) in growing Japanese quail diets improved growth performance, immune response, and health.

Effect of dietary supplementation of garlic powder and phenyl acetic acid on productive performance, blood haematology, immunity and antioxidant status of broiler chickens

OBJECTIVE

The effect of garlic powder (GP) and phenyl acetic (PA) acid throughout the fattening period of broiler chickens on performance, blood parameters, immune, and antioxidant parameters as well as carcass traits was evaluated.

METHODS

A total of 210 day-old Cobb broiler chicks were randomly distributed into seven dietary treatments having five replications with six chicks per replicate. The first group (control) fed a basal diet without supplements, whereas the 2nd, 3rd, and 4th group were fed basal diet plus 0.25, 0.50, and 0.75 g GP/kg diet, respectively and the group 5th, 6th, and 7th were fed on the basal diet plus 0.25, 0.50, and 0.75 g PA/kg diet.

RESULTS

Broiler body weight and gain at 21 and 42 days were increased (p<0.05) with diets supplemented with GP and PA. Red blood cells and hemoglobin were improved in chickens fed diets enriched with GP. Broiler chickens received diets containing either GP or PA recorded the higher values (p<0.05) of total protein, globulin, high-density lipoprotein, immunoglobulin M (IgM), and IgG, superoxide dismutase and total antioxidant capacity; while, blood total cholesterol, low-density lipoprotein, aspartate-aminotransferase, and malondialdehyde were lowered (p<0.05) compared to control-diet. Liver and immune-related organs weight were improved (p<0.05) in broilers fed diet supplemented with GP and PA.

CONCLUSION

Feeding of GP or PA in diet had positive effects on performance traits and immunological, antioxidant and physiological status of broilers. Thus, the use of tested feed additives as an eco-friendly alternative to antibiotics produced a positive effect on animal health.