Teleost Piscidins-In Silico Perspective of Natural Peptide Antibiotics from Marine Sources.

Fish, like all other animals, are exposed to constant contact with microbes, both on their skin and on the surfaces of their respiratory and digestive systems. Fish have a system of non-specific immune responses that provides them with initial protection against infection and allows them to survive under normal conditions despite the presence of these potential invaders. However, fish are less protected against invading diseases than other marine vertebrates because their epidermal surface, composed primarily of living cells, lacks the keratinized skin that serves as an efficient natural barrier in other marine vertebrates. Antimicrobial peptides (AMPs) are one type of innate immune protection present in all life forms. AMPs have been shown to have a broader range of biological effects than conventional antibiotics, including antibacterial, antiviral, antiprotozoal, and antifungal effects. Although other AMPs, such as defensins and hepcidins, are found in all vertebrates and are relatively well conserved, piscidins are found exclusively in Teleost fish and are not found in any other animal. Therefore, there is less information on the expression and bioactivity of piscidins than on other AMPs. Piscidins are highly effective against Gram-positive and Gram-negative bacteria that cause disease in fish and humans and have the potential to be used as pharmacological anti-infectives in biomedicine and aquaculture. To better understand the potential benefits and limitations of using these peptides as therapeutic agents, we are conducting a comprehensive study of the Teleost piscidins included in the "reviewed" category of the UniProt database using bioinformatics tools. They all have amphipathic alpha-helical structures. The amphipathic architecture of piscidin peptides and positively charged residues influence their antibacterial activity. These alpha-helices are intriguing antimicrobial drugs due to their stability in high-salt and metal environments. New treatments for multidrug-resistant bacteria, cancer, and inflammation may be inspired by piscidin peptides.

Efficient Oral Priming of Tenebrio molitor Larvae Using Heat-Inactivated Microorganisms.

Microbial resistance is a global health problem that will increase over time. Advances in insect antimicrobial peptides (AMPs) offer a powerful new approach to combat antimicrobial resistance. Invertebrates represent a rich group of animals for the discovery of new antimicrobial agents due to their high diversity and the presence of adaptive immunity or "immune priming". Here, we report a priming approach for Tenebrio molitor that simulates natural infection via the oral route. This oral administration has the advantage of minimizing the stress caused by conventional priming techniques and could be a viable method for mealworm immunity studies. When using inactivated microorganisms for oral priming, our results showed an increased survival of T. molitor larvae after exposure to various pathogens. This finding was consistent with the induction of antimicrobial activity in the hemolymph of primed larvae. Interestingly, the hemolymph of larvae orally primed with Escherichia coli showed constitutive activity against Staphylococcus aureus and heterologous activity for other Gram-negative bacteria, such as Salmonella enterica. The priming of T. molitor is generally performed via injection of the microorganism. To our knowledge, this is the first report describing the oral administration of heat-inactivated microorganisms for priming mealworms. This technique has the advantage of reducing the stress that occurs with the conventional methods for priming vertebrates.

Antimicrobial Activity of Cathelicidin-Derived Peptide from the Iberian Mole Talpa occidentalis.

The immune systems of all vertebrates contain cathelicidins, a family of antimicrobial peptides. Cathelicidins are a type of innate immune effector that have a number of biological functions, including a well-known direct antibacterial action and immunomodulatory function. In search of new templates for antimicrobial peptide discovery, we have identified and characterized the cathelicidin of the small mammal Talpa occidentalis. We describe the heterogeneity of cathelicidin in the order Eulipotyphla in relation to the Iberian mole and predict its antibacterial activity using bioinformatics tools. In an effort to correlate these findings, we derived the putative active peptide and performed in vitro hemolysis and antimicrobial activity assays, confirming that Iberian mole cathelicidins are antimicrobial. Our results showed that the Iberian mole putative peptide, named To-KL37 (KLFGKVGNLLQKGWQKIKNIGRRIKDFFRNIRPMQEA) has antibacterial and antifungal activity. Understanding the antimicrobial defense of insectivores may help scientists prevent the spread of pathogens to humans. We hope that this study can also provide new, effective antibacterial peptides for future drug development.

Antimicrobial Resistance in the COVID-19 Landscape: Is There an Opportunity for Anti-Infective Antibodies and Antimicrobial Peptides?

Although COVID-19 has captured most of the public health attention, antimicrobial resistance (AMR) has not disappeared. To prevent the escape of resistant microorganisms in animals or environmental reservoirs a "one health approach" is desirable. In this context of COVID-19, AMR has probably been affected by the inappropriate or over-use of antibiotics. The increased use of antimicrobials and biocides for disinfection may have enhanced the prevalence of AMR. Antibiotics have been used empirically in patients with COVID-19 to avoid or prevent bacterial coinfection or superinfections. On the other hand, the measures to prevent the transmission of COVID-19 could have reduced the risk of the emergence of multidrug-resistant microorganisms. Since we do not currently have a sterilizing vaccine against SARS-CoV-2, the virus may still multiply in the organism and new mutations may occur. As a consequence, there is a risk of the appearance of new variants. Nature-derived anti-infective agents, such as antibodies and antimicrobial peptides (AMPs), are very promising in the fight against infectious diseases, because they are less likely to develop resistance, even though further investigation is still required.

Bioinformatic Analysis of Genome-Predicted Bat Cathelicidins.

Bats are unique in their potential to serve as reservoir hosts for intracellular pathogens. Recently, the impact of COVID-19 has relegated bats from biomedical darkness to the frontline of public health as bats are the natural reservoir of many viruses, including SARS-Cov-2. Many bat genomes have been sequenced recently, and sequences coding for antimicrobial peptides are available in the public databases. Here we provide a structural analysis of genome-predicted bat cathelicidins as components of their innate immunity. A total of 32 unique protein sequences were retrieved from the NCBI database. Interestingly, some bat species contained more than one cathelicidin. We examined the conserved cysteines within the cathelin-like domain and the peptide portion of each sequence and revealed phylogenetic relationships and structural dissimilarities. The antibacterial, antifungal, and antiviral activity of peptides was examined using bioinformatic tools. The peptides were modeled and subjected to docking analysis with the region binding domain (RBD) region of the SARS-CoV-2 Spike protein. The appearance of multiple forms of cathelicidins verifies the complex microbial challenges encountered by these species. Learning more about antiviral defenses of bats and how they drive virus evolution will help scientists to investigate the function of antimicrobial peptides in these species.

Antibodies targeting enzyme inhibition as potential tools for research and drug development.

Antibodies have transformed biomedical research and are now being used for different experimental applications. Generally, the interaction of enzymes with their specific antibodies can lead to a reduction in their enzymatic activity. The effect of the antibody is dependent on its narrow i.e. the regions of the enzyme to which it is directed. The mechanism of this inhibition is rarely a direct combination of the antibodies with the catalytic site, but is rather due to steric hindrance, barring the substrate access to the active site. In several systems, however, the interaction with the antibody induces conformational changes on the enzyme that can either inhibit or enhance its catalytic activity. The extent of enzyme inhibition or enhancement is, therefore, a reflection of the nature and distribution of the various antigenic determinants on the enzyme molecule. Currently, the mode of action of many enzymes has been elucidated at the molecular level. We here review the molecular mechanisms and recent trends by which antibodies inhibit the catalytic activity of enzymes and provide examples of how specific antibodies can be useful for the neutralization of biologically active molecules.

Can Immunization of Hens Provide Oral-Based Therapeutics against COVID-19?

In the current worldwide pandemic situation caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and the newest coronavirus disease (COVID-19), therapeutics and prophylactics are urgently needed for a large population. Some of the prophylaxis strategies are based on the development of antibodies targeting viral proteins. IgY antibodies are a type of immunoglobulin present in birds, amphibians, and reptiles. They are usually obtained from egg yolk of hyper-immunized hens and represent a relatively inexpensive source of antibodies. Specific IgY can be produced by immunizing chickens with the target antigen and then purifying from the egg yolk. Chicken IgY has been widely explored as a clinical anti-infective material for prophylaxis, preventive medicine, and therapy of infectious diseases. Administered non-systemically, IgY antibodies are safe and effective drugs. Moreover, passive immunization with avian antibodies could become an effective alternative therapy, as these can be obtained relatively simply, cost-efficiently, and produced on a large scale. Here, we highlight the potential use of polyclonal avian IgY antibodies as an oral prophylactic treatment for respiratory viral diseases, such as COVID-19, for which no vaccine is yet available.

Milk Replacer Supplementation with Docosahexaenoic Acid from Microalgae Does Not Affect Growth and Immune Status in Goat Kids.

Consumption of polyunsaturated fatty acids (PUFA), especially docosahexaenoic acid (DHA), has beneficial effects for consumers' health. Consequently, there is an increased interest in enhancing meat fatty acid profiles (i.e., PUFA and DHA content) through diverse nutritional strategies. This study aimed to investigate the effect of supplementing a microalgae-derived product rich in DHA on growth and immune system development in newborn goat kids. In this experiment, newborn goat kids were fed milk replacer (MR) supplemented with three levels of a microalgae-derived product rich in DHA (DHA-Gold®, Martek Biosciences, MD, USA). Groups were designed as follows: MR-NS (milk replacer without DHA-Gold® supplementation; n = 10), MR-DHA-9 (9 g of DHA-Gold®/L milk replacer; n = 10) and MR-DHA-18 (18 g of DHA-Gold®/L milk replacer; n = 10). The immune status of the kids was evaluated by the plasma IgG and IgM concentrations, as well as by the complement system and chitotriosidase activities. Dietary supplementation with DHA did not affect either growth or innate and humoral immunity (p > 0.05). This study concludes that supplementation with DHA does not cause negative effects on growth and immune status in newborn goat kids.

Sheep and goats raised in mixed flocks have diverse immune status around parturition.

Several physiological and metabolic changes take place in dairy ruminants around parturition (late pregnancy, parturition, and early lactation). Dairy species are genetically selected for their higher milk production compared with non-dairy species. This fact causes a constant stress that impairs the immune status of the animal, with consequences for its welfare and performance. In the present study, we assessed the immune status of high-yield dairy sheep and goats by quantifying IgG and IgM concentrations, as well as chitotriosidase (ChT) and complement system [total complement system (TC) and alternative complement pathway (AC)] activity in blood plasma around parturition. We also measured IgG and IgM concentrations and ChT activity in colostrum and milk during the first 40 d postpartum. The lowest blood IgG concentration was at parturition in both species. We detected no differences in blood IgG concentrations between species. Blood IgM concentrations were constant in both species throughout the study period. However, blood IgM concentrations were greater in sheep than in goats. Blood ChT activity was greater in goats than in sheep, and both species showed constant activity of this enzyme throughout the study period. We observed no differences in complement system (TC and AC) activity between sheep and goats. In addition, both TC and AC activity were constant in both species throughout the experiment. In general, IgG and IgM concentrations were greater in sheep colostrum than in goat colostrum, but these differences disappeared after d 4 (IgG) and d 3 (IgM) postpartum. In both species, the highest IgG and IgM concentrations were measured in colostrum, gradually decreasing during the first days postpartum. Chitotriosidase activity decreased in both species from colostrum to milk, although goats always showed greater ChT activity than sheep. Both sheep and goats seemed to be more susceptible to infectious diseases around parturition. As well, goats showed greater ChT activity in blood, colostrum, and milk than sheep. This fact may give these animals additional protection against parasite and fungal infections.

Guinea pig for meat production: A systematic review of factors affecting the production, carcass and meat quality.

In developing countries, interest in guinea pig farming is growing exponentially because it provides a regular source of high quality animal protein for domestic consumption. Guinea pigs (Cavia porcellus) are prolific animals, grow and are capable of reproduction on a flexible diet, and are adaptable to a wide range of climates. This article mainly reviews findings on guinea pig meat production, including factors affecting raising guinea pigs, carcass and meat quality. We also present some studies that describe biological and pathologic effects on carcass component composition. During the last decades no standard procedure has been established for guinea pig carcass evaluation, which makes very difficult any comparison of results with other studies around the world. Herein we highlight a variety of factors that significantly affect carcass and meat quality. Some of these factors are production systems, environmental and genetic factors, management systems, the diet and health status, age, sex and reproductive management.

Short-term effects of milking frequency on milk yield, milk composition, somatic cell count and milk protein profile in dairy goats.

Goats in Canary Islands are milked once a day by tradition, but in most countries with high technology on farms, goats are milked twice a day, which is known to improve milk yield. Therefore it is important to know whether the increase of milking frequency can improve the production without impairing milk quality. The objective of this study was to investigate the short term effects of three milking frequencies on milk yield, milk composition, somatic cell count (SCC) and milk protein profile in dairy goats traditionally milked once a day. Twelve Majorera goats in early lactation (48±4 d in milk) were used. During a 5-week period, goats were milked once a day (X1) in weeks 1 and 5, twice a day (X2) in weeks 2 and 4, and three times a day (X3) in week 3. Milk recording and sampling were done on the last day of each experimental week. Milk yield increased by 26% from X1 to X2. No differences were obtained when goats were switched from X2 to X3, and from X3 to X2. The goats recovered the production level when they returned to X1. Different patterns of changes in the milk constituents due to the milking frequency effect were observed. Fat percentage increased when switched from X1 to X2, then decreased from X2 to X3, and from X3 to X2, whereas it did not show significant differences from X2 to X1. Milking frequency did not affect the protein and lactose percentages. SCC values were unaffected when goats were milked X1, X2 and X3, but then they increased slightly when milking frequency was returned to X2 and X1. Finally, quantitative analysis showed an increase in intensities of milk protein bands from X1 to X2, but the intensities of casein bands (α(S1)-CN, α(S2)-CN, ß-CN, κ-CN) and major whey proteins (α-La, ß-Lg) decreased from X2 to X3.

Body live weight and milk production parameters in the Majorera and Palmera goat breeds from the Canary Islands: influence of weight loss.

Seasonal weight loss (SWL), caused by poor quality pastures during the dry season, is the major limitation to animal production in the tropics. One of the ways to counter this problem is to breed animals that show tolerance to SWL. The objective of this study was to understand the effect of feed restriction in milk production and live weight (LW) evolution in two goat breeds, with different levels of adaptation to nutritional stress: the Majorera (considered to be tolerant) and the Palmera (considered to be susceptible). A total of ten animals per breed were used. Animals were divided in four groups (two for each breed): a restricted group (restricted diet) and a control group. LW and milk yield parameters were recorded through a trial that lasted 23 days in total. Overall, there were no significant differences between both restricted groups, regarding neither LW nor milk yield reductions (LW reduction 13 % and milk yield reduction of 87 % for both restricted groups). In what concerns control groups, there were no significant differences between breeds, thought there were different increments at the end of the trial for both breeds regarding LW (6 and 4 %, for Majorera and Palmera, respectively) and milk yield (28 and 8 %, respectively for Majorera and Palmera). The lack of statistically significant differences between Palmera and Majorera LW and milk yields in restricted groups may be due to the fact that the controlled trial does not replicate harsh field conditions, in which Majorera would excel, and the stress induced by those differences.

The effect of diet and DHA addition on the sensory quality of goat kid meat.

To enhance the nutritional quality of meat, dietary strategies have been developed to manipulate the fatty acid profiles of muscle tissue. Fatty acids affect meat attributes, including hardness, colour and lipid stability, and flavour. Little research has been done, however, on the effects of dietary omega-3 polyunsaturated fatty acid (PUFA) supplementation on the sensory characteristics of meat. To address this issue, six diets were fed to goat kids: goat's milk, powdered whole cow's milk, powdered whole cow's milk plus docosahexaenoic acid (DHA) (low dose), milk replacer, milk replacer plus DHA (low dose), and milk replacer plus DHA (high dose). A descriptive, semi-trained sensory evaluation and a consumer triangular test were performed to analyse the resulting meat. High doses of omega-3 PUFA produced meat with unusual odours, unpleasant flavours, and low overall appreciation scores. Low doses of DHA maintained a positive sensory perception.

The effects of storage temperature on goat milk somatic cell count using the DeLaval counter.

This study investigated the influence of storage temperature and storage time on goat milk somatic cell counts (SCCs) determined using the DeLaval cell counter (DCC). SCCs were measured in 40 Majorera goat milk samples using the DCC device. Samples were grouped from high score (>2,750 x 10(3) cells/mL) to low score (<630 x 10(3) cell/mL) according to the SCC. Each milk sample was divided into four aliquots and stored at four different temperatures (4 degrees C, 21 degrees C, 36 degrees C or 45 degrees C). The SCC was recorded every hour for 12 hours. Storage of goat milk with a high SCC for 5, 5, 2 or 1 hour at 4 degrees C, 21 degrees C, 36 degrees C or 45 degrees C, respectively, decreased the SCC value compared to fresh milk. The goat milk SCC was lower after 1 hour of storage than that determined for fresh milk at any tested temperature in low-SCC samples. The data presented herein suggest that regardless of storage temperature, goat milk samples should not be stored for more than 1 hour before measurement of SCC with a DCC device.