Special Issue "Animal Nutrition and Sustainability: Insects and Agricultural By-Products as Animal Feed Ingredients"

A special issue of Veterinary Sciences (ISSN 2306-7381). This special issue belongs to the section "Nutritional and Metabolic Diseases in Veterinary Medicine".

Deadline for manuscript submissions: 15 March 2024 | Viewed by 7690

Special Issue Editor

Department of Veterinary Sciences, University of Pisa, Viale delle Piagge 2, 56124 Pisa, Italy
Interests: animal science; food quality; edible insects

Special Issue Information

Dear Colleagues,

It is well known that current feed and food production are environmentally unsustainable. New research insights have shown that insects and agricultural by-products could contribute to the sustainability of animal nutrition.

For this Special Issue, we are interested in research papers or reviews aimed at evaluating the use of insects or agricultural by-products derived from agronomy practices, the food industry, or market disposal, as ingredients for animal feed, in order to reduce loss in the production chain while improving the health status of the livestock and the nutritional quality of the products.

Dr. Simone Mancini
Guest Editor

Manuscript Submission Information

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Keywords

  • insect
  • agricultural
  • by-product
  • sustainability
  • environmental impact
  • feed

Published Papers (6 papers)

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Research

12 pages, 1198 KiB  
Article
Behaviour of Staphylococcus aureus in the Rearing Substrate of Tenebrio molitor Larvae
Vet. Sci. 2023, 10(9), 549; https://doi.org/10.3390/vetsci10090549 - 01 Sep 2023
Viewed by 864
Abstract
Tenebrio molitor (mealworm) is one of the most promising insect species to produce sustainable feed and food with high nutritional value. Insects may harbour microorganisms both in the gut and on the exoskeleton originating from the rearing environment. Staphylococcus aureus is a pathogenic [...] Read more.
Tenebrio molitor (mealworm) is one of the most promising insect species to produce sustainable feed and food with high nutritional value. Insects may harbour microorganisms both in the gut and on the exoskeleton originating from the rearing environment. Staphylococcus aureus is a pathogenic microorganism frequently involved in food poisoning due to its enterotoxin production. This study aimed to evaluate the S. aureus growth and enterotoxins production following an experimental inoculation into the T. molitor rearing substrate (about 7 log CFU/g). Analyses on the substrate and larvae were performed over a testing period of seven days. The microbial population dynamics were also evaluated through total viable count and lactic acid bacteria count. The effects of fasting, washing, and cooking on the microbial loads of mealworms were evaluated. The results highlighted that mealworms and substrates can maintain their microbial loads of S. aureus over the tested period. Moreover, fasting and washing were generally not able to significantly reduce (p-value > 0.05) S. aureus count in mealworms. On the other hand, cooking significantly reduced (p-value < 0.001) the microbial load in almost all cases. No production of enterotoxins was revealed during the trial. Therefore, microbiological risks can be reduced by a wise choice of substrate, appropriate control measures, and thermal treatment of larvae. Full article
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18 pages, 1704 KiB  
Article
Grape Pomace: Agrifood By-Product with Potential to Enhance Performance, Yolk Quality, Antioxidant Capacity, and Eggshell Ultrastructure in Laying Hens
Vet. Sci. 2023, 10(7), 461; https://doi.org/10.3390/vetsci10070461 - 13 Jul 2023
Viewed by 807
Abstract
Grape pomace (GP) is an industrial by-product of grape juice making and is commonly discarded as a waste product, even with its large quantity of phytochemicals. Thus, the objectives of this trial were to examine the effects of graded dietary GP on laying [...] Read more.
Grape pomace (GP) is an industrial by-product of grape juice making and is commonly discarded as a waste product, even with its large quantity of phytochemicals. Thus, the objectives of this trial were to examine the effects of graded dietary GP on laying rate, egg quality, yolk lipid profile, oxidative stability, shell quality and ultrastructure, and serum biochemistry. Two hundred 35-week-old laying hens were allocated to four dietary treatments with ten replicates each. Four diets were formulated by mixing a standard basal diet with GP at 0 g/kg (control), 30 g/kg (GP3%), 60 g/kg (GP6%), and 90 g/kg (GP9%). Egg production percent, egg weight, and egg mass were linearly improved (p < 0.01) due to adding GP to the diets of laying hens. Eggs obtained from laying hens fed with GP diets had (p < 0.01; linear, p < 0.01) greater Haugh units, yolk color, albumen index, and yolk index than those of the control. The GP9% group had the greatest values (p < 0.05) for shell weight, thickness, and breaking strength. Electron microscopy scanning of eggshells indicated that the incremental dietary level of GP linearly augmented the thickness of the palisade layer but reduced both the mammillary layer and mammillary knob width (p < 0.01). Improved tibia-breaking strength and ash content were shown (p < 0.05) in the GP-fed laying hens. The dietary addition of GP by up to 90 g/kg linearly (p < 0.01) mitigated lipid oxidation and improved the antioxidant capacity in both the serum and stored eggs. A reduction in the percentages of saturated fatty acids was observed, while the contents of monounsaturated fatty acids, polyunsaturated fatty acids, and n-3 fatty acids were augmented because of increasing dietary GP levels (p < 0.001). Additionally, the eggs obtained from laying hens fed on the GP6% and GP9% had lower yolk cholesterol content (p < 0.001); this effect was confirmed by linear and quadratic responses (p < 0.001). Laying hens on GP diets had lower (p < 0.01) serum hepatic enzymes, cholesterol, triglycerides, and low-density lipoprotein but greater high-density lipoprotein compared to the control. To sum up, the addition of GP in the layers’ diets by up to 90 g/kg increased laying performance, enriched the yolk with beneficial fatty acids, enhanced antioxidant potential in yolk lipids, and improved shell quality and ultrastructure. Full article
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14 pages, 1147 KiB  
Article
Effects of Feeding Different Levels of Sprouted Barley on Fermentation Characteristics, Bacterial Quantification, and Rumen Morphology of Growing Lambs
Vet. Sci. 2023, 10(1), 15; https://doi.org/10.3390/vetsci10010015 - 26 Dec 2022
Cited by 1 | Viewed by 1155
Abstract
The objective of the present study was to investigate the effects of sprouted barley inclusion level on the growth performance, digestibility, volatile fatty acids, bacterial quantification, and rumen morphology of growing lambs. Five dietary treatments with sprouted barley (0, 25, 50, 75 and [...] Read more.
The objective of the present study was to investigate the effects of sprouted barley inclusion level on the growth performance, digestibility, volatile fatty acids, bacterial quantification, and rumen morphology of growing lambs. Five dietary treatments with sprouted barley (0, 25, 50, 75 and 100%) and nine replicates per dietary treatment were performed on forty-five Awassi lambs (90 days old). The average weight gain, intake, and digestibility of dry and organic matter were recorded. The pH, color, volatile fatty acids, bacterial quantification, and rumen histomorphometry were also determined. The results showed that the average dry and organic matter intake in T2 to T4 and the average weight gain in T4 decreased linearly. In contrast, the digestibility of dry and organic matter by sprouted barley (T2 to T4) was higher. The pH values and rumen color were not affected. Concentrations of formic acid, acetic acid, butyric acid, and the ratio of acetic acid to propionic acid were increased, while lactic acid and total volatile fatty acids were lower in all levels of sprouted barley. In addition, lambs fed T4 had a higher quantification of Anaerovibrio Lipolytica, Butyrivibrio Fibrisolvens, and Streptococcus Bovis quantification. Selenomonas Ruminantium was higher in T1, T2, and T4, whereas Megashpaera Elsdenii was lower in T1 to T3. The rumen histomorphometric was improved by sprouted barley (T2 and T3). Sprouted barley improved digestibility and rumen histomorphometry and increased the concentration of some volatile fatty acids and rumen bacteria but resulted in a decrease in average dry and organic matter intake, which negatively affected weight gain in lambs fed 100 % sprouted barley. Further studies are required to determine the potential effects on growing lambs fed sprouted barley. Full article
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16 pages, 1311 KiB  
Article
The Chemical Composition, Fermentation End-Product of Silage, and Aerobic Stability of Cassava Pulp Fermented with Lactobacillus casei TH14 and Additives
Vet. Sci. 2022, 9(11), 617; https://doi.org/10.3390/vetsci9110617 - 07 Nov 2022
Cited by 2 | Viewed by 1531
Abstract
This study evaluated the effects of cassava pulp fermented with Lactobacillus casei TH14, urea, and molasses on its chemical composition, the fermentation end-product of silage, and aerobic stability. A 2 × 2 × 2 factorial arrangement with a randomized complete block design was [...] Read more.
This study evaluated the effects of cassava pulp fermented with Lactobacillus casei TH14, urea, and molasses on its chemical composition, the fermentation end-product of silage, and aerobic stability. A 2 × 2 × 2 factorial arrangement with a randomized complete block design was employed. The first factor: level of L. casei TH14 [L; 0 and 105 cfu/kg fresh matter (FM)], the second factor: level of molasses (M; 0 and 4% DM), the third factor: level of urea (U; 0 and 4% DM), and the number of days of fermentation (7, 14, and 21 days) were evaluated using a statistical block. There were interactions among CSP fermented with different additives on DM content (p < 0.05). The control group (CON) and CSP fermented with L, L×M, and L×U had lower DM contents than U, U×M, and L×U×M. The crude protein of CSP was increased by interaction of L×U and U×M additives (p < 0.05 and p < 0.01, respectively). Interaction effects between L and U and NDF content were detected (p < 0.05). The L×U combination resulted in a significantly lower NDF than the other groups. The interaction between L×U×M had no effect on the change in the CSP fermentation process (p > 0.05). The combination of U×M caused a poorer pH than other groups (p < 0.01). The ammonia-N content was higher than others, when CSP was fermented with L×U (p < 0.01) or U×M (p < 0.05), respectively. The lactic acid levels in fermented CSP were higher (p < 0.01) than in other groups through the L. casei. The interaction between L×U×M had an influence on lactic acid bacteria (LAB) (p < 0.01) and aerobic bacteria (p < 0.01). The highest LAB population (p < 0.01) at 106 cfu/g FM was found in CSP fermented with L. casei and molasses. In conclusion, the current study shows that CSP treated with L×U×M resulted in good preservation by recovering DM, a low number of aerobic bacteria, and greater LAB than other treatments, with the exception of the L×U×M addition. A 21-day fermentation period is advised because it produces products with greater levels of crude protein, lactic acid, acetic acid, and propionic acid. Full article
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9 pages, 265 KiB  
Article
Utilization of Mao (Antidesma thwaitesianum Muell. Arg.) Pomace Meal to Substitute Rice Bran on Feed Utilization and Rumen Fermentation in Tropical Beef Cattle
Vet. Sci. 2022, 9(11), 585; https://doi.org/10.3390/vetsci9110585 - 23 Oct 2022
Cited by 2 | Viewed by 1322
Abstract
This experiment was conducted to investigate the effects of replacing rice bran with mao pomace meal on feed intake, digestibility, and rumen fermentation in beef cattle. Four crossbred (50% Brahman × 50% Thai native) beef cattle with an initial body weight of 195 [...] Read more.
This experiment was conducted to investigate the effects of replacing rice bran with mao pomace meal on feed intake, digestibility, and rumen fermentation in beef cattle. Four crossbred (50% Brahman × 50% Thai native) beef cattle with an initial body weight of 195 ± 13 kg and 16 months of age were used in a 4 × 4 Latin square design. The dietary treatments included four levels of RB replacement with mao pomace meal at 0, 33, 67, and 100% in concentrate diets. Rice straw was used as a roughage source, fed ad libitum. Replacement of mao pomace meal with rice bran did not affect (p > 0.05) the intakes of concentrate, rice straw, and total dry matter intake. Ether extract intake decreased linearly when increasing the levels of mao pomace meal (p < 0.01). The experimental diets had no effect (p > 0.05) on the digestibility of fiber and crude protein, while dry matter, organic matter, and ether extract digestibility decreased linearly in the group of mao pomace meal replacing rice bran (p < 0.05). Increasing levels of mao pomace meal in concentrate diets did not alter rumen pH, ammonia–nitrogen, or total volatile fatty acid concentration (p > 0.05). The proportion of propionate increased linearly (p < 0.05), whereas acetate and the acetate to propionate ratio decreased linearly (p < 0.05) when replacing rice bran with mao pomace meal. Moreover, the proportion of propionate was greatest, while acetate was lowest when mao pomace meal was included at 100% in the concentrate diet. In conclusion, the replacement of rice bran with mao pomace meal in a diet could enhance the efficiency of rumen fermentation. Nonetheless, it reduced the digestion of nutrients in tropical beef cattle. Full article
14 pages, 310 KiB  
Article
Effects of Feeding Housefly (Musca domestica) Larvae on the Butchery Skills and Meat Sensory Characteristics of Local Chickens in Niger
Vet. Sci. 2022, 9(10), 553; https://doi.org/10.3390/vetsci9100553 - 09 Oct 2022
Cited by 1 | Viewed by 1093
Abstract
The purpose of this work was to study the effects of substitution of fishmeal by housefly larvae at different rates and different physical states in the diet of local chickens. Five diets consisted of LFD, 25DL, 50DL, 25FL and 50FL, respectively, larval-free, 25%-dried-larvae, [...] Read more.
The purpose of this work was to study the effects of substitution of fishmeal by housefly larvae at different rates and different physical states in the diet of local chickens. Five diets consisted of LFD, 25DL, 50DL, 25FL and 50FL, respectively, larval-free, 25%-dried-larvae, 50%-dried-larvae, 25%-fresh-larvae and 50%-fresh-larvae diet, in which 0, 25 and 50% of fishmeal was replaced by dried and fresh larvae, was formulated. A total of 165 local chickens of three weeks old, divided into 15 boxes in batches of 11 animals were raised. The experiment consists of three replications of five treatments. At 14 weeks of age, sixty chickens were slaughtered. Butchery skills and sensory characteristics were evaluated. Thus, a small variation of the ultimate pH from 5.63 to 5.55 between the different types of meat, and a carcass yield around 66%, was recorded. Any effects of substitution rate and physical state of housefly larvae on growth performance was not observed. Feet and proventriculus percentages increased in chickens fed 25% substitution. Liver and spleen percentage, and redder breast meat, increased in chicken fed dried larvae. Yellowness of the breast, thigh-and-drumstick meat and juiciness increased with 50% substitution. There is need of an investigation for liver and spleen enlargement and housefly larvae containing pigments. Thus, housefly larvae up to 50% substitution can be a suitable alternative to fishmeal in local chicken diets. Full article
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