Amount Of Feed Research Articles

Effect of grazing hour on growth performance of crossbred sheep from southwest coastal region of Bangladesh

Sheep are small ruminants that require small amounts of feed and can graze on poor-quality pastures, including fallow lands, roadsides, dikes and playgrounds. Therefore, the experiment was conducted to evaluate the effect of the grazing length on growth performance of crossbred sheep in the southwestern region of Bangladesh. Sixteen crossbred female sheep were divided into four treatment groups and randomly allowed four different grazing periods. The experimental design was based on a randomized complete block design (RCBD). Lambs were initially weighed and grouped by keeping the average weight of the four treatment groups approximately the same. The grazing hours allocated to the four treatment groups were 6, 8, 10 and 12 hours, respectively. During this period, the sheep of particular treatment groups were housed when their allocated grazing period was completed. Empty body weight data were taken fortnightly in the morning before they were allowed to graze. The results revealed that body weight increased with increasing grazing length but the mean difference did not differ significantly (p>0.05). In most cases, the highest body weight was observed in sheep grazing for 12 hours per day. Average growth rates of grazing sheep varied significantly between the 6 to 8 hour and 10 to 12 hour grazing groups. But between the 6 to 8 hour grazing group and the 10 and 12 hour grazing group, the growth rate of crossbred sheep did not vary significantly (p>0.05). The growth rate (g day-1) of crossbred sheep ranged from 22.44±4.75 to 92.00±11.95, highest in 12 hour grazing group and lowest in 6 hour group. It can be concluded that the body weight and growth rate of crossbred sheep increased with an increase in grazing length. However, 10 hours of grazing meets the requirements for their maintenance and growth due to good pasture quality. Int. J. Agril. Res. Innov. Tech. 14(1): 104-107, June 2024

Enhancing Muscovy Duck Meat Quality and Growth Development Through Oregano Extract Supplementation: A Study in Agricultural Innovation

This study investigated the effects of oregano extract (OE) supplementation on the growth and meat quality of Muscovy ducks, aiming to optimize meat quality and explore sustainable dietary interventions in poultry production. Twenty-five male Muscovy ducks were meticulously allocated to five treatment groups, each comprising five replications, employing a Completely Randomized Design (CRD). Ducks were exposed to varying levels of oregano extract supplementation with five dietary treatments: T0 (control), T1 (25% OE), T2 (50% OE), T3 ( 75% OE), and T4 (100% OE). Throughout the 4-week trial period, individual ducks were accommodated in designated pens to facilitate precise monitoring. The investigation examined several growth parameters, including feed intake (FI, the amount of feed consumed by each duck), feed cost (FC, the expense associated with feeding each duck), weight gain (WG, the increase in body weight of each duck over the specified time period), and feed conversion ratio (FCR, the ratio of feed consumed to weight gained), assessed at weekly intervals. Results showed that OE supplementation did not significantly affect feed intake or weight gain, except for weeks 1 and 2 where T3, supplemented with 75% OE, exhibited the highest weight gain. However, OE supplementation significantly improved FCR, with T3 showing the lowest FCR, indicating enhanced nutrient utilization. Additionally, T3 displayed the highest fasted live weight, dressed weight, and dressing percentage, suggesting improved meat production and quality. Sensory analysis revealed that T3 consistently exhibited favorable meat quality attributes. Overall, T3 demonstrated the highest general acceptability among consumers, based on criteria such as taste, texture, and overall satisfaction. The study highlights the potential of OE supplementation to optimize feed efficiency and enhance meat quality in Muscovy ducks.

Management factors associated with the survival and market weight of broiler chickens among small-scale farmers in the Dodoma City of Tanzania

Broiler chickens have the genetic potential for significant weight gain over a very short period of time. As a result, they account for over 92 % of the world's poultry meat production in different parts of the world. Yet, to fully realise their growth potential, effective management practices are crucial, encompassing aspects like nutritious feeds, disease control, optimal temperature, and adequate housing. The purpose of the study was to determine the management practices associated with the survival and market weight of broiler chickens in small-scale production. Small-scale poultry production plays a significant role in poverty reduction and household nutrition in developing countries. One hundred and forty small-scale broiler farmers were visited for interviews in the Dodoma City. Employing a structured questionnaire, data on management practices was gathered, while past production records determined market weight and survival rates. Most chickens weighed 1.8–2.3 kg at the end of the production cycle, with a mean live weight of 2.0 kg. Heat provision to chick housing in the early growth stages increased both survival and market weight. Conversely, chicken vaccination and the farmer's experiences were correlated with an increased survival rate. Furthermore, higher feed quantities offered to growers and finishers were linked to greater market weight. It was concluded that enhancing knowledge among small-scale farmers through training and extension services has the potential to increase broiler productivity.

Physiological effects of feeding whiteleg shrimp (Penaeus vannamei) with the fresh macroalgae Chaetomorpha clavata

In shrimp farming, the use of commercial feed can generate high nutrient loads in water bodies, and often constitute the most substantial component of production costs. Alternatives that seek to reduce the use of commercial feed can therefore both mitigate environmental impacts and reduce operational expenses. One possible strategy is incorporation of algae that crustaceans can consume with minimal biological effect into integrated multi-trophic aquaculture (IMTA) systems. Our objective was to determine whether the marine shrimp Penaeus vannamei feeds on the fresh macroalga Chaetomorpha clavata and whether the partial substitution (50 %) of this alga in its diet influences its physiology. Survival, growth, and a range of physiological processes including ingestion, defecation, metabolism, nitrogen excretion, oxidized energy substrate, hepatosomatic index, and energy budget were assessed in P. vannamei shrimp fed commercial feed (100 %, control) versus shrimp fed a combination of commercial feed and algae (50 % each). Our results showed that P. vannamei fed on C. clavata, and that there were no significant differences in mortality and growth rates (∼11 %) between shrimp fed with the two diets. The ingestion rate was higher in the group fed with macroalgae, however the defecation rate and digestibility were not affected. In both groups, no differences were detected in metabolic rates, growth, nitrogenous excretion, and egestion between shrimp fed the different diets, nor in oxidized energy substrates and the hepatosomatic index. Our results show that substituting 50 % of the feed with C. clavata represents a viable alternative to full commercial feed since it had minimal impact on the physiological functions of P. vannamei. In addition to the economic benefit of reducing the amount of feed used during culture, the use of algae also reduces contamination of effluent water, thereby improving environmental sustainability and water quality.

Gospodarowanie odpadami komunalnymi w czasie kryzysu geopolitycznego z punktu widzenia budżetu gminy

The article aims to present the problem of paying for municipal waste management in the face of the influx of refugees caused by the war in Ukraine. The number of people residing in Poland has significantly increased, and as a result more waste is generated. The authors analyse current legal regulations and judgments of administrative courts and the Constitutional Tribunal to determine who is obliged to pay the municipal waste management fee and what proper steps this entity should take. Due to the nature of the problem, the dogmatic-legal method was used to analyse the texts of legal acts, court decisions and available literature. The solution proposed by the authors can be used in practice by the bodies of local government units adjudicating the determination of the municipal waste management fee amount.

Agricultural land, governance, and institutional change: Evidence from a Bulgarian study

New Institutional Economics (NIE) uses solutions from law, economics and organization. The purpose of this article is to link in a single analytical approach the institutional environment, its change in the organizations uniting in one, what is happening in contracts with agricultural lands. The explanation of this type of governance means to integrate: theoretical definitions; formal rules (laws, court decisions and other legal acts); economic institutions—means and mechanisms of exchange; legal and economic forms in which, through governance of transactions property rights are transferred and protected. In order to achieve this goal, it is necessary to present the elements of the institutional matrix that are the cause of changes in subordination and coordination. Following the process of implementing an approach for reconciling the legal and economic nature of the contract forms and integrating the states, contract organizations and transaction costs in a common model. In order to solve the research problems tasks are adapted methods from law, economics, statistics. Such are: (a) positive legal analysis of legislation; (b) historical (retrospective) method of analysis of changes; (c) discrete-structural analysis to explain the process; (d) comparative-institutional analysis to clarify alternatives and an explanation of any of the effects; (е) regression analysis to model the relationships and present possible one’s scenarios to show the direction in which changes are needed. Changes in legislation, legal forms, mechanisms and the amount of payments create new behavioral patterns that change the contract. Therefore, in retrospect, we are witnessing how the number of changes in legal acts, the amount of fees; the number of participants-administrators of the processes; the number and registers - change the number of transactions; the duration of the actions in the contracts, which ultimately predetermines the different amounts of transaction costs for agricultural lands. This interdependence was established by constructing an econometric model. The analysis presents opportunities for change that would lead to scenarios with a reduced level of transaction costs, that is, improving governance and showing the way to improve the institutional environment related to agricultural lands in Bulgaria.

Open Access Models of Russian Academic Journals

Open access (OA) to publications has been a global trend in publishing academic journals for a long time. The number of OA journals, including Russian ones, is growing steadily. The purpose of this study was to determine the main trends in the implementation of open access publishing models in Russian research journals. The article presents the results of a study of 396 journals included in the Russian Science Citation Index database: title of a journal; website address; international classification code (OECD group); quartile; Science Index indicator; open access model; license type; section of a journal’s website that contains information about the absence or presence and amount of an article processing charge (APC). It is concluded that the majority of journals implement Bronze OA which, firstly, does not comply with the key principles of open access, because it does not use open licenses, and, secondly, does not provide any guarantees that open access will continue to be open. The lack of accessible and transparent information about the conditions for further use of publications can create serious legal issues for the licensee. In turn, it will most likely be a problem for authors to calculate the amount of publication fee.

Co-incorporation of Black Soldier Fly (Hermetia illucens) Larvae and Moringa (Moringa oleifera) Leaves in the Diet Increase African Catfish Profitability (Clarias gariepinus)

Aquaculture is a fast-growing activity in Cameroon and required substantial quantities of affordable protein-rich feed. In this study, we co-incorporated Moringa leaves (MOL) and black soldier fly larvae meal (BSFLM) in catfish diet, and the effect was evaluated on feed floatation, fish growth, flesh organoleptic qualities and profitability. 450 juvenile`s catfish weighing averagely 10 g, were subjected to five dietary treatments consisting of: T0 (0% BSFLM and 0% MOL); T1 (6.25% BSFLM and 5% MOL); T2 (12.5% BSFLM and 10% MOL); T3 (18.75% BSFLM and 15% MOL) and T4 (25% BSFLM and 20% MOL) for 119 days. The treatment T3 containing 18.75% BSFLM and 15% MOL recorded the highest floatation duration, fish weight (113.83±17.31 g) and weight gain (103.25±17.8 g), and the lowest feed conversion ratio (1.60±0.37). The flesh tasted good and was acceptable in all treatments. Incorporating BSFLM and MOL in the diets reduced the cost per kg of feed from 18 to 23%, thus increasing the system's profitability from 45.91 to 60.84%. We concluded that BSFLM and MOL can partially substitute fish meal in catfish diet and improve the profitability and offers insights into the development more profitable and sustainable aquaculture in Cameroon and globally.

Preparation of SiO2 nanotubes and nanoparticles in the presence of L-tartaric acid by sol-gel method and their electrochemical performance for Li-ion batteries

Recently, SiO2 has attracted increasing attention as an anode material for lithium-ion batteries (LIBs) owing to its low cost and high theoretical specific capacity. However, its inherent poor conductivity limits its practical application. To address this issue, nanostructured material design is considered an effective solution. Herein, based on the traditional ammonium tartrate template-directed sol-gel method, we use low-cost and easily available L-tartaric acid in place of D, L-tartaric acid to prepare high-yield silica nanotubes (SNTs) with a thin wall (ca. 50 nm), small diameter (ca. 150 nm), rough surface and open ends, as well as tiny spongy-like silica nanoparticles (SNPs) by adjusting the feeding amount and feeding mode of NH4OH solution. The electrochemical characterization results suggest that the SNTs show better cyclability and rate performance than the SNPs, which maintain a reversible capacity of 741.3 mAh g−1 after 500 cycles at a current density of 0.4 A g−1 and deliver a high rate capacity of 819.4 mAh g−1 at a high current rate of 2 A g−1. The excellent electrochemical performance suggests that hollow one-dimensional hollow nanotubes are more efficient in improving the electrochemical performance of SiO2 than zero-dimensional nanoparticles, and SNTs with thin tube walls and rough surfaces are demonstrated to be fascinating and promising anode materials for LIBs.

Effect of SNPs on Litter Size in Swine.

Although sows do not directly enter the market, they play an important role in piglet breeding on farms. They consume large amounts of feed, resulting in a significant environmental burden. Pig farms can increase their income and reduce environmental pollution by increasing the litter size (LS) of swine. PCR-RFLP/SSCP and GWAS are common methods to evaluate single-nucleotide polymorphisms (SNPs) in candidate genes. We conducted a systematic meta-analysis of the effect of SNPs on pig LS. We collected and analysed data published over the past 30 years using traditional and network meta-analyses. Trial sequential analysis (TSA) was used to analyse population data. Gene set enrichment analysis and protein-protein interaction network analysis were used to analyse the GWAS dataset. The results showed that the candidate genes were positively correlated with LS, and defects in PCR-RFLP/SSCP affected the reliability of candidate gene results. However, the genotypes with high and low LSs did not have a significant advantage. Current breeding and management practices for sows should consider increasing the LS while reducing lactation length and minimizing the sows' non-pregnancy period as much as possible.

Selection of host plants for production of Clanis bilineata (Lepidoptera: Sphingidae).

Clanis bilineata Walker (Lepidoptera: Sphingidae), a burgeoning edible insect, is experiencing rising demand in China and other regions. Despite this interest, larval production is currently constrained by the limitations of artificial production technologies, particularly the selection of optimal host plants. This study rigorously evaluated the performance of C. bilineatha larvae on four main host plants: round-leaf soybean, pointed-leaf soybean, black locust, and kudzu. Preference tests demonstrated that the larvae were most attracted to black locust (34.76 ± 4.65%), with subsequent preferences for kudzu (25.00 ± 6.12%), round-leaf soybean (23.17 ± 2.79%), and pointed-leaf soybean (14.02 ± 4.74%). No significant preference differences were noted between round-leaf soybean and either black locust or kudzu. In feeding assays, the larvae exhibited a marked preference for round-leaf soybean (37.36 ± 0.81 g, total feeding amount for larvae), followed by kudzu (37.26 ± 0.82 g), pointed-leaf soybean (35.38 ± 1.31 g), and black locust (28.53 ± 0.81 g). When the larvae were fed on round-leaf soybean, they exhibited significantly higher survival rate (39.33 ± 0.90%), body weight (9.75 ± 0.07 g), total biomass (383.43 ± 7.35 g), pupation rate (87.78 ± 1.73%), and egg production (189.80 ± 1.06 eggs/female) compared to other hosts. These findings uncovered that round-leaf soybean significantly enhances larval performance, suggesting its potential for improving C. bilineata larval production and sustainability in cultivation systems.

Effects of four types of natural bait on water quality, feeding, growth, and antioxidant enzyme activity of Monopterus albus in a recirculating aquaculture system

Monopterus albus is one of China’s renowned and superior aquaculture species, with its seedlings mainly sourced from wild capture. One of the bottlenecks in M. albus aquaculture is the high mortality rate and low feeding initiation rate from stocking wild fry to the initiation of feeding. In production, trash fish is commonly used to wean M. albus juveniles onto feeding. In this study, we introduced three other natural feeds, earthworms (EW), yellow mealworms (YMW), and fly maggots (FM), with frozen trash fish (TF) serving as the control group, to evaluate the effects of these four natural feeds on the survival rate, feeding initiation, antioxidant enzymes activity, and body composition of M. albus juveniles under recirculating water aquaculture conditions. The experiment comprised four treatments, each with three replicates. Each replicate consisted of stocking 150 M. albus juveniles weighing 10.02 ± 0.89 g in size, raised for 5 weeks. The survival rate of the YMW group was 73.33%–85.33%, which was significantly higher than that of the other three bait groups (p < 0.05). The four bait groups showed no significant differences in final body weight and specific growth rate (SGR) (p > 0.05). The EW group showed the highest final body weight, with an average SGR of 2.73, whereas the YMW group had an average SGR of 1.87. The average daily feeding amount was significantly higher in EW and YMW groups than in the other two groups (p < 0.05). The percentage of feeding amount to fish weight in the EW group reached 7.3% in the fifth week. After 5 weeks of cultivation, NO2−-N content was significantly higher in the waters of the TF and EW groups than in the waters of the FM and YMW groups (p < 0.05), there was no significant difference in TAN content among the treatment groups (p > 0.05). Liver malondialdehyde content was significantly higher in the TF group than in the other bait groups (p < 0.05). GSH-Px activity was significantly higher in the EW group than in the FM group and YMW group. No significant differences in SOD and CAT activity and T-AOC were observed among the bait groups (p > 0.05). The increase in crude protein content was significantly higher in the TF group than in the FM group, but the increase in crude ash content was significantly lower in the TFgroup. In conclusion, Tenebrio molitor could potentially serve as one of the alternative feeds during the initial stages of M. albus juveniles stocking.

Potential use of pineapple crop residue silage to replace sorghum silage for crossbred lactating cows

The use of crop residue silages is a viable alternative for producers to reduce feed costs. The present study was developed with the objective of investigating the inclusion of pineapple silage in replacement of sorghum silage in the diet of lactating cows regarding feed intake, production, and quality of milk. Eight crossbred (Holstein × Gir) cows with an average weight of 555±30 kg and an average milk yield of 12.50±3.25 kg/day, between 60 and 90 days in milk, were distributed into two simultaneous 4 × 4 Latin squares, at one animal per experimental unit. Silage of pineapple crop residue (PS) using plants after the harvest of the fruits was included in the roughage portion of the diet at increasing levels, with simultaneous and proportional removal of sorghum silage (SS) from the diets. The studied treatments thus consisted of the roughage portion containing: 1- 0% PS and 100% SS (100SS); 2- 34% PS and 66% SS (34PS66SS); 3- 67% PS and 33% SS (67PS33SS); 4- 100% PS and 0% SS (100PS). The diets were supplied twice daily, allowing 5% leftovers in relation to the quantity offered. The amounts of feed supplied, and orts of each animal were weighed for a subsequent determination of intake. The experiment was divided into four 21-day sub-periods, the first 14 days of which were used as an adaptation to the diet, while the others served for data collection. The milk was weighed from the 15th to the 19th day of each experimental period, and milk samples were collected on the last day of each period. Milk samples were sent to the laboratory, where they were analyzed. Dry matter, mineral matter, and lignin concentrations in the diet did not vary (P>0.05) as a function of PS inclusion in the roughage portion, while protein content, fiber content, and fat content levels were influenced. No effect of PS inclusion was observed (P>0.05) on the intakes of dry matter, neutral detergent fiber, mineral material, or lignin. However, PS inclusion prompted (P<0.05) a linear increase in the intakes of protein and total fat. The inclusion of pineapple plant silage in the roughage part of the diet had a positive effect (P<0.05) on milk yield, 4% fat-corrected milk yield, and on the milk fat and total solids contents. Milk production, as well as fat and total solids content, increased moderately with inclusion of pineapple plant silages in the roughage portion of the diet. Therefore, pineapple silage can replace sorghum silage in the roughage part of diets for lactating crossbred cows.

Feed particle size matters for the larval growth of Alphitobius diaperinus (Panzer) but not for Tenebrio molitor L. (Coleoptera: Tenebrionidae)

AbstractThe effect of the particle size of the feed on the larval growth and feed utilization parameters of two mealworm species, Alphitobius diaperinus (Panzer) and Tenebrio molitor L. (Coleoptera: Tenebrionidae), was examined under laboratory conditions. Wheat bran of four different particle sizes (100–250, 500–650, 850–1000 and >2000 μm) was provided as feed to larvae of both species. The larval growth and survival, as well as time to pupation and the amount of feed consumed, were monitored to determine differences among the wheat bran particle sizes within each insect species. Our research results suggest that a finely ground feed with a particle size below 650 μm significantly impact the growth and development of A. diaperinus, as opposed to a feed containing particles larger than 850 μm. Contrariwise, the larvae of T. molitor exhibited no discernible response to the various feed particle sizes that were evaluated. Overall, it was observed that the two mealworm species did not exhibit identical responses for the tested feed particle size, suggesting that this factor is species dependent.

Individual cage housing affects feed intake and induces sex-specific effects on body weight in Japanese quails

Individual cage housing in poultry production could be a potentially stressful environment for the birds that can alter feed intake, consequently induce negative effects on performance. Previous studies used individual bird-based experiments to extract the detailed molecular, physiological, and fitness outcomes of treatments. Understanding sex-specific effects of isolation on social birds such as Japanese quails (Coturnix japonica) may reveal important considerations. To understand this phenomenon, birds were kept in groups of 10 for one week and they were kept in individual cages for another week. Daily feed intake (DFI) was measured each day and body weight was measured at the beginning, middle, and end of group rearing and at the beginning and end of individual rearing. It was found that both males and females showed a reduction DFI in response to individual rearing (p<0.0001). Females consumed on average 29.38% higher amount of feed than males. Additionally, females showed a pronounced reduction in body weight after isolation, while the effect on males was not significant. Similarly, females had on average 17.61% higher body weight than males. The body weight to DFI ratio was higher in males than females. The finding of this research revealed an important implication of isolation and sex differences.

A novel automated approach for fish biomass estimation in turbid environments through deep learning, object detection, and regression

Estimating fish biomass is crucial in the fisheries sector, where traditional methods often harm fish through manual sampling and anesthetics. A non-invasive approach is introduced using underwater films to estimate fish biomass in turbid conditions. This study presents the “Aquatic WeightNet” dataset, targeting the Genetically Improved Formed Tilapia (GIFT) Tilapia species, and addresses the challenge of unclear images with preprocessing techniques like dehazing and Contrast Limited Adaptive Histogram Equalization (CLAHE). YOLOv8, a leading object detection model modified to accommodate the custom Aquatic WeightNet dataset's varied image sizes with five detection heads, P2 to P6, is employed, achieving a recall of 0.997 and a mean Average Precision (mAP) of 0.899 within the 50–95% Intersection over Union (IoU) range. Fish biomass estimation assesses depth, length, and width using regression models for calculation. A three-phase grid search identifies the most effective models, with the Extra Trees Regressor outperforming depth estimation with mean absolute error (MAE) of 0.63 and coefficient of determination (R2) of 0.87 and the Random Forest Regressor for length and width (MAE of 0.01 and R2 of 0.99). For biomass estimation, the Extra Trees Regressor again performs well (MAE of 0.004 and R2 of 0.99), which is critical for determining optimal feed quantities to enhance aquaculture efficiency. This study emphasizes a non-invasive method to estimate fish biomass, optimizing the effectiveness and ecological sustainability of fish farming in murky waters through advanced detection algorithms and robust regression models.

Real-time ammonia estimation in recirculating aquaculture systems: A data assimilation approach

Recirculating aquaculture systems offer sustainable fish production but face challenges related to ammonia levels. Ammonia, particularly the un-ionized fraction, NH3, can negatively impact fish growth and health. Traditional ammonia estimation methods, including offline analyses and affordable, yet inaccurate, in-situ measurements, lack the ability to provide reliable real-time insights. Data assimilation combines simulation models and in-situ measurements to provide more accurate estimations. In this study, we demonstrate a novel approach using data assimilation to enhance real-time ammonia estimation in RAS. First, ammonia dynamics are described by forming equations that constitute a simulation model, based on the feeding amounts and the biofilter removal rate parameters. Then, an extended Kalman filter is presented and customized to integrate the simulation model and total ammonia nitrogen measurements for estimating NH3, NH4+, and biofilter parameters. We validated our method through synthetic and laboratory case studies and demonstrated its superior estimation capability as compared to in situ measurements or simulation models. Furthermore, improved ammonia estimation led to improved current and future fish weight estimations, which can be essential for reliable RAS management. The proposed approach facilitates wider adoption of DA in challenging estimations in aquaculture.

Automatic Cattle Feeder

The cattle need to be fed. It is a simple statement, but one that resonates with every cattle producer. To make this necessary task easier for farmers, the concept of automatic cattle feeding system came into existence. Automatic Cattle Feeding System is a robotic feeding system which consists of battery operated robotic system that is capable of feeding an equal amount of feed. The feed is manually loaded in the feeder After the feed is mixed in the mixer, it falls onto the conveyer belt and follows a predetermined path until it reaches the last cattle in the fence. To ensure the precise, timely and adequate feeding of each cattle, this project is applicable in an agricultural country where the lack of manpower is there in cattle farming. Due to less man power there is an adverse effect on dairy production. The main objective is to design an automatic cattle feeding system that it moves around the fence to distribute the feed uniformly. With the application of following robotic system , remarkable changes can be brought to this field. . The use of PIC microcontroller helped to control and switch off the whole system whenever there is any issue in the hardware. With the application of Automatic Cattle Feeding system uniformity and hygiene in feed distribution can be maintained

Mycophagous Mite, Tyrophagus putrescentiae, Prefers to Feed on Entomopathogenic Fungi, except Metarhizium Generalists.

(1) Background: The mycophagous mite, Tyrophagus putrescentiae, was found to feed on entomopathogenic fungi (EPF) in our previous experiments, which seriously impacted the culture and preservation of fungal strains. Therefore, it is necessary to investigate the biological characteristics of the occurrence and damage to EPF. (2) Methods: The mite's growth and development and feeding preference were surveyed by comparative culture and observation; also, optical and electronic microscopies were employed. (3) Results: T. putrescentiae could survive normally after being fed on seven EPF species, including Purpureocillium lilacinum, Marquandii marquandii, Cordyceps fumosorosea, Beauveria bassiana, Metarhizium flavoviride, Lecanicillium dimorphum, and Metacordyceps chlamydosporia. The first four fungi were the mite's favorites with their greater feeding amount and shorter developmental duration. Interestingly, the mite could also feed on Metarhizium anisopliae and Metarhizium robertsii, but this led to the mite's death. After feeding on M. anisopliae and M. robertsii, the mites began to die after 24 h, and the mortality rate reached 100% by 72 h. Observation under optical microscopy and scanning electron microscopy revealed that the conidia of M. anisopliae and M. robertsii adhered to the mite's surface, but there was no evidence of penetration or invasion. However, dissection observation indicated that the two Metarhizium species germinate and grow within the mite's digestive tract, which implies that Metarhizium generalists with broad-spectrum hosts and the production of destruxins have acaricidal activity toward the mycophagous mites.

Improvement of the recombinant phytase expression by intermittent feeding of glucose during the induction phase of methylotrophic yeast Pichia pastoris.

For growth of methylotrophic yeast, glycerol is usually used as a carbon source. Glucose is used in some cases, but not widely consumed due to strong repressive effect on AOX1 promoter. However, glucose is still considered as a carbon source of choice since it has low production cost and guarantees growth rate comparable to glycerol. In flask cultivation of the recombinant yeast, Pichia pastoris GS115(pPIC9K-appA38M), while methanol induction point(OD600) and methanol concentration significantly affected the phytase expression, glucose addition in induction phase could enhance phytase expression. The optimal flask cultivation conditions illustrated by Response Surface Methodology were 10.37 OD600 induction point, 2.02h before methanol feeding, 1.16% methanol concentration and 40.36μL glucose feeding amount(for 20mL culture volume) in which the expressed phytase activity was 613.4 ± 10.2U/mL, the highest activity in flask cultivation. In bioreactor fermentation, the intermittent glucose feeding showed several advantageous results such as 68h longer activity increment, 149.2% higher cell density and 200.1% higher activity compared to the sole methanol feeding method. These results implied that remaining glucose at induction point might exhibit a positive effect on the phytase expression. Glucose intermittent feeding could be exploited for economic phytase production and the other recombinant protein expression by P. pastoris GS115.