Amount Of Feed Research Articles

Scalable Nickel Catalysts for Carbonylative Terpolymerization of Ethylene/α-Olefin with High Efficiency.

The carbonylative polymerization of olefin yields aliphatic polyketones, which are used as engineering plastics in the market due to their excellent mechanical strength, chemical resistance, and surface and barrier properties. However, the usage of precious palladium catalysts has restricted their extensive application as commodity materials. Herein, we present a series of phosphine-sulfonate Ni catalysts with a wide spectrum of electronic and steric substituents on the phosphorus moiety for the carbonylative polymerization of ethylene. Such efficient nickel-catalyzed copolymerization shows the on-demand transformation of ethylene/CO gas to polyketones with quantitative yield and product specificity. A remarkable productivity of up to 20 kg PK (g Ni)-1 was obtained during ethylene/propylene/CO terpolymerization, and the polymerization productivity is independent of the type and feeding amount of α-olefin. The resulting terpolymers show comparable crystallinity, thermal stability, and tensile properties with commercial POKETONE products from Hyosung. The nickel catalyst also features the advantages of using cheap raw material sources and simple synthetic procedures that can be scaled up easily, which enables it to be a promising candidate for industrial application.

Research on palatability of bait for targeted control of Brandt's vole (Lasiopodomys brandtii) in typical steppes

Chemical control is still the primary means of controlling wild rodent pests in China's grasslands; however current rodenticides are broad-spectrum and pose a risk to several other grassland ecosystems. Improving the precision of grassland rodent pest control and reducing collateral damage to non-target animals is an urgent problem. One solution to this problem is to ensure that bait choices are preferred by specific rodent. However, most studies on the development of rodenticides have neglected bait choice. We focused on Brandt's voles (Lasiopodomys brandtii), the dominant rodent species in the typical steppes of China, in this study. By measuring the percentage of feeding amount (PFA) different baits in a cafeteria setting, we sought to test the palatability of different candidate baits. We found that one of our blend baits was as popular as the wheat bait among Brandt's voles under laboratory conditions. However, our blended bait was preferred to the wheat bait when rodenticide was added. Non-target animals Columba livia, Gallus domesticus, Ovis aries, and sympatric non-target rodents feed less on blended bait than on wheat. We also used field trials to test whether baits were removed by Brandt's voles or PFA of partially consumed baits. In the wild, the removal time and PFA of Brandt's voles for the rodenticide + blend bait were better than those for the rodenticide + wheat bait. Mixing the wheat baits with bromadiolone rodenticide made poisoned baits less attractive to prey species than unpoisoned baits; however, Brandt’s voles were more likely to take the tainted baits than the unpoisoned baits when bromadiolone was added to the blends. Our results suggested that blend bait with 80 % Allium polyrhizum+ 20 % Stipa krylovii was highly palatable to Brandt's voles, did not become less palatable when poisoned with rodenticide, and was less likely to be eaten by non-target species including Columba livia, Gallus domesticus, Cricetulus barabensis, Phodopus campbelli and Ovis aries. Thus, blend bait has the potential to improve the pest management of Brandt's voles in China.

무인자동 양식어류 급이공급 시스템 개발 및 검증

Unmanned automatic feeding systems are being actively distributed to automate land-based aquaculture farms. Currently, feed supply in aquaculture is primarily based on a fixed period and amount, depending on the predetermined feed quantity set by the operator, which does not consider the dynamic feed supply needs of fish. This can lead to under- or oversupply of feed, affecting the fish growth rate and water quality in aquaculture. To address this, a method is proposed in this paper to identify fish hunger levels using machine vision and predict the dissolved oxygen concentration in real time to prevent mass fish mortality due to water quality deterioration, even with additional feed supply. The method aims to verify its performance. Firstly, based on the observation that aquaculture farm operators estimate fish hunger levels by feeding time, a method is proposed to estimate hunger levels using machine vision and feeding time. Next, a combination of time series data decomposition model and pre-trained deep learning model is used to predict the dissolved oxygen concentration in real time.

A Practical Economic Order Quantity Model for Growing Items with Edible Yield and Constraints in Poultry Farming

Growing items like chicken broilers play a critical role in consumption baskets; however, their real characteristics have been neglected in the research focusing on inventory models such as economic order quantity (EOQ). Mainstream research conducted in this field considers an approximation of the edible rate of chicken broilers in cost analysis. On the other hand, this subject was the objective of other research, and the function that represents the relationship between the weight and age of broilers was derived through extensive research. This study proposes an EOQ model that considers a realistic function for extracting the exact value of edible parts of broilers and the correct form of feeding function that is dependent on their age. In other words, this study not only addresses the challenge arising in the estimation of the edible part of broilers but also introduces another function to obtain the correct amount of feeding and nurturing cost of broilers. Solution methodology encompasses these mathematical functions and then provides a straightforward framework to find the optimal solution. An exact heuristic solution is obtained that considers the real factors, and then the approach is applied to case studies, and insights are derived to manage real situations for corporations.

Unbalance detection of threshing cylinder in non-stationary rotation based on variational mode extraction

The rotating speed of the threshing cylinder was hardly constant in practice due to transmission error and cylinder speed would change with feed quantity to ensure the grain threshing effect. This paper proposed a novel unbalance detection method for non-stationary rotation. Variational mode extraction (VME) was introduced to extract unbalanced vibration signal and the unbalance feature index (UFI) was constructed as a criterion of weighting factor selection. Moreover, the unbalance phase calculation method and phase reference in non-stationary were proposed, which could eliminate the influence of speed change. The advantages of VME and UFI were verified by simulation, and the effectiveness of proposed method was proved by experiment on multi-cylinder test rig and combine harvest. This method could realize the reconstruction of unbalanced vibration signal in time-varying speed with low computational cost, break the strict requirement of constant speed of the existing balancing method.

Effect of dietary supplementation with oregano oil premix on the antioxidant status, performance, and meat quality in slow-growth broiler chickens

This study investigated the influence of dietary supplementation with oregano oil premix on the antioxidant status, performance, and meat quality of slow-growth genotype chickens raised under a commercial production system. The study included two groups, with nine replicates: Group A) 54.000 broilers raised in free-range farms and fed the basal diet, and Group B) 27.000 broilers raised in free-range farms and fed the basal diet supplemented with oregano oil premix. Oregano oil was blended with a standard premix (120 g/ton), which was then mixed with the feed (amount adjusted on the growth stage). The results showed that serum total antioxidant capacity (TAC) was significantly higher (p ≤ 0.05) in the non-supplemented group compared to the dietary-supplemented group with oregano oil premix. In contrast, thigh muscle total antioxidant capacity was significantly increased in the supplemented group compared to the non-supplemented group (p ≤ 0.05). There were no differences in serum and thigh muscle Thiobarbituric Acid Reactive Substances (TBARS) and performance parameters between the two groups. Chickens fed with the oregano oil premix exhibited increased protein and ash content, pH value, and higher smell, taste, and colour scores compared to the non-supplemented group. Summarising, our large-scale in field study showed that incorporating oregano oil premix in slow-growth and free-range chickens’ diet improves the thigh muscle total antioxidant capacity and meat quality. The results indicate that the oregano oil premix positively impacts the nutritional value of the final product. However, more research is needed under in field conditions to draw a safer conclusion.

Design and Parameter Optimization of a Rigid–Flexible Coupled Rod Tooth Threshing Device for Ratoon Rice Based on MBD-DEM

To solve the problem of the high loss rate of threshing devices during the mechanical harvesting of ratoon rice, we propose a method using the principle of rigid–flexible coupling in this paper to reduce losses. Through analysis of the forces and collisions on ratoon rice grains during the threshing process, it has been confirmed that changing the structure and materials of the threshing contact components can effectively reduce grain loss. A rigid–flexible coupling rod tooth was designed, and the overall structural parameters of the device were determined based on force analysis results and dimensional boundary conditions. The MBD-DEM coupling method was used to simulate the threshing process, and the force conditions of the threshing rod teeth and threshing drum were obtained. The influence of the feeding amount and of the flexible body thickness on the crushing of ratoon rice grains was analyzed. In order to obtain the device’s optimal parameter combination, a three-factor quadratic regression orthogonal rotation combination experiment was conducted with drum speed, flexible body thickness, and rod tooth length as experimental factors. The optimization results showed that when the drum speed, flexible body thickness, and rod tooth length were 684 r/min, 3.86 mm, and 72.7 mm, respectively, the crushing rate, entrainment loss rate, and uncleaned rate were 1.260%, 2.132%, and 1.241%, respectively. The bench test showed that it is feasible to use the MBD–DEM coupling method to measure the motion and force of ratoon rice. The rigid–flexible coupling threshing device can reduce the grain crushing rate while ensuring grain cleanliness. Compared with traditional threshing devices, the crushing rate and entrainment loss rate of the rigid–flexible coupling threshing device were reduced by 55.7% and 27.5%, respectively. The research results can provide a reference for the design of threshing devices for ratoon rice harvesters.

Bioactivity-Based Analysis and Chemical Characterization of Hypoglycemic Components from Helicteres angustifolia L.

Helicteres angustifolia L. (H. angustifolia), a well-known traditional Chinese medicine, has been demonstrated to have hypoglycemic activity. We found that the EtOAc extract of H. angustifolia (HAEF) showed stronger α-glucosidase inhibitory activity than that of positive control. Furthermore, the hypoglycemic activity of HAEF was evaluated in streptozotocin (STZ)-induced type 2 diabetes mellitus (T2DM) rats. The results demonstrated that HAEF reduced the drinking quantity, feeding quantity, and controlled weight loss in diabetic rats. Besides, the fasting blood glucose (FBG), viscera index, and the area under time-blood glucose curve (AUC) were significantly decreased, and the oral glucose tolerance was also improved after 5 weeks. Then, the high-performance liquid chromatography with quadrupole time of flight tandem mass spectrometry (HPLC-Q-TOF-MS/MS) method was performed for qualitative analysis of the chemical constituents in HAEF. Twenty-one compounds were identified from in HAEF. Four compounds were further isolated from HAEF and subjected to α-glucosidase inhibition experiments. At the end, molecular docking was empolyed simulate the interaction of three compounds with α-glucosidase. This is the first report on major hypoglycaemic components has been identified in the roots of H. angustifolia. These findings provide a material basis for the use of H. angustifolia in the treatment of diabetes.

VARIASI PAKAN DALAM MENDUKUNG PRODUKTIVITAS SAPI ACEH DAN SAPI BALI DI INDONESIA

The survival of Acehnese and Balinese cattle is affected by feed that contains nutrients to support the growth and productivity of livestock. Feed quality, quantity and continuity are problems that affect the productivity of local cattle in Indonesia. The most commonly used forages in feeding Aceh and Bali cattle are elephant grass dan field grass, while the most commonly used concentrates are palm fronds and corn. A combination of 80% forage and 20% concentrate tends to be better for increasing daily weight gain of Aceh and Bali cattle.

The impact of the 2012 student fees increase on the mental health of British graduates: a cohort study

PurposeFinancial difficulties are associated with poor student mental health, although the 2012 tuition fees increase for British students had little impact on student mental health in the first two years at university. This study aims to examine the mental health of British graduates before and after this fees increase to determine the impact on mental health several years after graduation.Design/methodology/approachThis study conducted an online cohort study with 327 British students who started university before and after the 2012 fees increase. Participants completed measures of current economic hardship and symptoms of depression, anxiety, stress, general mental health and suicidality. Multiple regression was used to examine the impact of cohort (pre- and post-2012 fees increase), tuition fees amount and economic hardship on mental health.FindingsGreater economic hardship was positively correlated with all mental health variables. Starting university after the fees increased and/or paying greater fees was associated with increased depression, anxiety, stress and suicidality, with little impact on general mental health. When economic hardship was covaried, the strength of cohort effects reduced but remained significant.Originality/valueTo the best of the authors’ knowledge, this is the first study to show that the 2012 tuition fees increase for British students increased depression, anxiety, stress and suicidality in graduates many years after graduation, owing to additional financial strain.

Efficacy of phytase and/or chromium tripicolinate supplementation on dry matter and nitrogen digestibility and blood metabolites in grower pigs.

Phytase supplementation is widely used throughout the world for enhancing nutrient use efficiencies in pigs, while added chromium has been shown to help stabilize glucose metabolism by enhancing insulin sensitivity. Therefore, the objectives of this metabolism study were to examine the potential synergies of these additives to see if nutrient digestibilities and/or blood metabolites could be improved in grower pigs. A total of 12 Genesus terminal genetics grower pigs (20.7 kilograms (kg)) were allotted randomly in a crossover experiment with four periods and four dietary treatments based on a 2 x 2 factorial design via two groups. This provided 12 replicates per dietary treatment. Treatment (Trt) 1 consisted of a control diet without phytase while Trt 2 had decreased levels of soybean meal, calcium (Ca) and phosphorus (P) with added phytase (1,500 phytase units (FYT)/kg, HiPhorius®; dsm-firmenich, Plainsboro, NJ). The nutrient release values for amino acids, calcium and phosphorus were via standard recommendations from dsm-firmenich for the phytase. Treatment 3 consisted of the control diet without phytase with 200 parts per billion (ppb) of added chromium from chromium tripicolinate (Chromax®, Kent Nutrition Group, Inc., Muscatine, IA) while Trt 4 consisted of the diets with decreased levels of soybean meal, Ca and P with added HiPhorius (1,500 FYT/kg) and Chromax (200 ppb). With six metabolism crates available, four, one-week-long periods were utilized to evaluate each of the four treatments with each pig with two groups evaluated and pooled for data analysis. The pigs were allowed a 4-d acclimation period followed by a 3-d collection period with the experimental diets fed at 4% body weight each day. Water was administered to each pig at 2.5 times the amount of feed fed each day. On the last day of the collection period, blood samples were collected before the meal (fasting) and then two h after the meal (postprandial). There were no significant differences among treatments for both fasting and postprandial glucose and insulin levels. Added phytase resulted in a reduction (P < 0.05) in fasting blood urea nitrogen (N). Nitrogen digestibility and retention and dry matter (DM) digestibility were all improved (P < 0.01) with pigs fed supplemental phytase. Supplemental chromium was without effect on any of the N and DM digestibility measurements. These data suggest that supplemental phytase has positive effects for improving N and DM digestibilities.

Extent of Locally Sourced Feed Ingredients and Performance of Feed Mill Entreprises in Southwest, Nigeria

Promoting local sourcing of raw materials for firms in Nigeria has become one of the critical areas of government policies. In achieving this, the government introduced a ban on the importation of grains/cereals, which are critical ingredients in feed production for the feed mill industry. Hence, this study examines the extent (share) of locally sourced feed ingredients and its implications on the performance of feed mills in Southwest, Nigeria. Primary data used for this study was analysed using descriptive statistics and fractional probit regression. Firm’s age, quantity of feed produced and location of the feed mills significantly determined the share of locally sourced feed ingredients in feed production of feed mills in the region while level of education of feed mill operators, firm’s age, quantity of feed produced and proportion of locally sourced feed ingredients had significant effect on the performance (profitability) of feed mill entreprises in the area. It was therefore recommended that policies on improving infrastructure, production of feed ingredients, and addressing insecurity should be prioritised rather than promoting a ban on the importation of critical feed ingredients for the feed mill industry in Nigeria.

Evaluating Black Soldier Fly and Bloodworm Larvae Meals as Sustainable Protein Sources for Growth and Survival of Red Hybrid Tilapia (Oreochromis spp.) in the Nursery Phase

Aims: This study aimed to assess the effects of using insect larvae meals, such as BSF and BW larvae, as alternative feeds to commercial pellets on the growth performance and survival of Oreochromis spp. at the nursery stage. Study Design: This study followed the randomized control treatment with three different diet. Place and Duration of Study: This study was carried out at the Fisheries Research Institute Glami Lemi (FRIGL) in Negeri Sembilan, Malaysia, within 35 days from July to August 2023. Methodology: A total of 360 red hybrid tilapia (Oreochromis spp.) fingerlings weighing 0.62 ± 0.06 g were randomly distributed into 12 rectangular aquarium tanks (250mm) at a stocking density of 30 fish per tank. They were fed with commercial pellets (CP), Black Soldier Fly (BSF) larvae, and Bloodworm (BW). The feed amount was calculated at 10% of the total body weight per tank, with feeding conducted three times daily. The experimental setup was performed in triplicate. For the analysis of growth performances and fish survival, sampling was conducted weekly. Results: BSF larvae meal had high lipid and protein content, measuring 35.35 ± 0.21% and 29.67 ± 0.98%, respectively. BW larvae meal also showed high lipid and protein content, with 28.23 ± 1.33% and 27.94 ± 0.52%, respectively. Fish fed with BSF and BW larvae exhibited significantly higher survival rates, 93.3 ± 3.3% and 86.7 ± 14.5%, respectively, compared to the control group. Meanwhile, the group fed with the commercial pellet showed the lowest survival rate, just 74.4 ± 12.6%. Fish fed with the BW larvae recorded the highest weight gain, 1.07 ± 0.16 g, followed by fish fed with BSF larvae, 0.66 ± 0.11 g, and then fish fed with commercial pellets, 0.41 ± 0.09 g. Conclusion: Both BSF and BW larvae exhibited significant growth response properties to tilapia fingerings compared to commercial pellets. The findings from this study are promising and should be further verified at the farm scale.

Description of Complementary Feeding Practice to Underweight Children Under Two Years Old in The Working Area of Puskesmas Kanor, Bojonegoro District

Children under two years of age, are in a very important developmental period often referred to as the Golden Age. Child classified as Underweight based on anthropometry, measurements if their body weight for Age (BB/U) is between -3 SD &lt;-2 SD. According to data from the Bojonegoro District Health Service. This study aims to describe complementary feeding practice to underweight children aged 6-24 months with in the working area of the kanor community health center. Research used an interview method with a questionnare for data collectin, A total of 41 children were selected through random sampling. The result showed that the age at first complementary feeding was correct in 68.4% of cases however, frequency 75.6%, amount 63.4%, texture 75.6%, variation 53, 6%, responsiveness 58.5% and hygiene 58.5%. While most children had a story of exclusive breastfeeding, aspect such as children had a history of exclusive breasfeeding aspect such as frequency, quantity, texture, variety, and responsivenness of complementary feeding were incorrect even though cleanliness was satisfactory. Educational interventions are needed to improve knowledge and practices related to proper complementary feeding for children.

Comparative Analysis of Intestinal Morphology and Gut Microbiota of Spinibarbus sinensis Under Different Aquaculture Systems.

Fish gut health is influenced by various factors, with the environment being a significant one. S. sinensis is a key aquaculture species in China, yet research on the impact of different aquaculture systems on its intestinal health remains limited. This study aims to explore the changes in intestinal morphology and gut microbiota of S. sinensis under two aquaculture systems. The juveniles of S. sinensis were divided into two groups and cultured in traditional ponds (CT) and an in-pond tank culture system (JY), with equal amounts of feed provided daily over a 72-day experimental period. The results showed no significant differences in growth performance metrics, including the specific growth rate, weight gain rate, hepatosomatic index, and viscerosomatic index between the two groups. In terms of intestinal morphology, the JY group villus width was significantly wider than the CT group, and the number of goblet cells in the CT group was significantly higher than that of the JY group (p < 0.05), which suggested that the fish in the JY group may have better intestinal nutrient absorption capacity, while the water quality in the CT group may be worse. The 16S rRNA gene sequencing analysis of the gut microbiota showed that the JY group had a significantly higher Shannon index compared to the CT group (p < 0.05), indicating greater species richness and evenness. Principal Coordinates Analysis (PCoA) revealed a distinct clustering of gut microbiota between the two groups. At the phylum level, the relative abundance of Fusobacteriota was significantly higher in the CT group, whereas Bacteroidota and Proteobacteria were significantly higher in the JY group (p < 0.05). Furthermore, KEGG pathway predictions indicated differences in the potential metabolic capabilities of the gut microbiota between the two groups (p < 0.05). Overall, this study is the first to conduct a comparative analysis of the growth performance, intestinal tissue morphology, and gut microbiota of S. sinensis under two different aquaculture systems, which has valuable implications for the further optimization of aquaculture practices.

Modelling the impact of increasing supplementary feed allowance on predicted sheep enterprise production, profit and financial risk across southern Australia

Context Supplementary feeding may alter sheep enterprise production and profit margin, but use may vary across regions, sheep breeds and mating seasons. Supplementary feeding is a means of ensuring adequate nutrition but increases operating costs. Modelling has previously indicated the most profitable sheep enterprises optimise stocking rate and target lamb production, whereas those that minimise supplementary feeding incur the least financial risk. Aims To explore the impact of increasing supplementary feed allowance on production, profit and financial risk. Methods Seventy-two sheep farm enterprises were simulated across eight southern Australian locations, including three breeds and three mating seasons. For each enterprise a low grain allowance (LGA) of 30 kg/head.year (threshold used in previous modelling) was compared to a high grain allowance (HGA) of 35 kg/head.year and 42 kg/head.year for Merino and non-Merino ewes (current industry recommendations), respectively. The financial risk of each enterprise was determined via Conditional Value at Risk of gross margins over 30 years, exploring downside risk in the worst 20% of scenarios. Key results A HGA increased production and profit in 32% of farm enterprises, but financial risk was often increased. Merino enterprises were generally the most profitable, least risky and consumed the greatest amount of supplementary feed, followed by Composite and then Maternal enterprises. Summer and autumn mating was often most profitable, but high supplement consumption in autumn-mated enterprises increased financial risk. Conclusions Increasing supplementary feeding may improve production and profit but may also increase financial risk using the parameters examined. Implications Producers may be able to improve the production, profit and financial risk of an enterprise through increased supplementary feeding, but this will be dependent on breed, input costs, commodity prices and location.

Short-term reduction in feed intake by dairy cows in the postpartum period leads to subclinical ketosis development

Subclinical ketosis is widespread in highly productive dairy cows after calving and often remains undiagnosed, leading to reduced productivity. Physiologically controlled feeding in the first weeks after calving and during the intensive lactation period can reduce the incidence of ketosis. The study aimed to determine how a short-term reduction of feed after calving affects the formation of ketone bodies in blood, urine and milk of dairy cows. The group of ten Ukrainian black-spotted dairy breed cows after calving aged from 4 to 6 years was involved in the experiment lasted for 72 h. In 24 h the amount of compound feed, haylage, and silage received by cows was gradually reduced until complete exclusion in the diet. Blood, urine, and milk samples were collected three times a day. The content of ketone bodies, β-hydroxybutyrate and glucose was estimated with the corresponding sets of indicator strips. The content of total bilirubin, cholesterol, albumin and enzymes activity in the blood serum were determined on biochemical analyzer. It was found that in 24 h after the beginning of feed reduction the level of blood glucose decreased, persistent hypoglycemia within 48 and 72 h was developed, the concentration of β-hydroxybutyrate in blood and milk and of ketone bodies in urine was elevated. The increase in total bilirubin concentration and liver enzymes activity in the blood serum with a simultaneous decrease in albumin level and delayed sodium propionate conversion into glucose were observed. Thus, short-term reduction in feed intake by dairy cows after calving causes ketosis development and violation of liver functions. Keywords: dairy сows, feeding level, glucose, ketosis, liver damage, β-hydroxybutyrate

Improvement of energy efficiency and production performance in a heteroazeotropic batch distillation unit: A study on decanter control and feeding strategy

Dehydration of methyl isobutyl ketone (MIBK) using a batch distillation unit has been investigated through process simulation. Applying a decanter for upgrading the heteroazeotropic distillation is analyzed in different aspects. The unit performance dependency on the feed quantity, decanter design/control policy, decanter holdup volume, and subsequent phase separation quality are evaluated in detail. Feed quantity is recognized as a key factor influencing unit performance. Although increasing the feed quantity leads to a higher production rate (SPF) and lower specific energy cost (SEC), the optimal feed quantity is identified as the point beyond which further improvements in these variables become negligible. Also, reflux initiating time, liquid–liquid separation grade, loss of the desired component along with the effluent stream, and holdup loss at the end of the process are recognized as functions of decanter holdup quantity. Accordingly, a perfect decanter with a large holdup volume is not necessarily the best option. The evaluation indicates that an effective decanter lies on a larger aqueous phase holdup and smaller organic phase holdup, as long as it is capable of efficiently separating the liquid phases (over 75% separation efficiency for each phase). It is found that applying a well-designed and properly controlled decanter for the mixture separation (MIBK-water) can improve the unit recovery by up to 6% and the production rate (and energy cost) by up to 7% compared to a conventional batch distillation unit. Furthermore, an inverted batch distillation configuration with a gradual feeding policy is applied as an alternative and compared to other operation policies. The feeding schedule is found to be the key factor in this mode. The results reveal that an inverted distillation unit equipped with a properly designed and controlled decanter provides up to 17% improvement in energy and production rate as well as 7% in recovery for a 9% shorter process time compared to a conventional batch distillation unit.

Body weight optimization of broiler breeder hens. 1. Pullet growth, feed efficiency, carcass composition, and sexual maturation

This study aimed to evaluate the effect of early growth (EG) and time of maximum pubertal growth peak (I2) on development, feed efficiency, carcass composition, and sexual maturation of broiler breeder females. Target BW trajectories were designed by changing coefficients of a 3-phase Gompertz model fit to the recommended BW target of Ross 308 breeders, BW=∑i=1i=3giexp(−exp(−bi(t−Ii))). In each phase i, biologically relevant coefficients describe the amount of BW gain (gi), the rate of growth (bi), and the inflection point (Ii), which is the time when the growth rate for that phase is at its maximum rate. The study consisted of a 6 × 2 factorial arrangement, with six I2 levels (I from phase 2) and two EG levels. The I2 coefficients were 15, 17, 19, 21 (standard), 22, and 23 in wk. The EG treatments were: EG0, where g1 and g2 coefficients estimated from the standard from the breeder recommended BW were unchanged; and EG20, where 20% of the gain (g2) in phase 2 (pubertal phase) was shifted to phase 1 (g1; prepubertal phase). Two-hundred-eighty-eight Ross 308 pullets were randomly assigned to the twelve BW growth trajectories and fed using a precision feeding system from 0 to 28 wk of age. Body composition variables were submitted to three-way ANOVA, with EG, I2, and age as fixed sources of variation. Analysis of covariance was conducted on the remaining dependent variables with EG as fixed effect, I2 as a continuous fixed effect, and age as continuous random effect. Differences were reported at P ≤ 0.05. The BW of females followed their target BW, and ADFI differed depending on the amount of feed required to achieve their respective BW targets. Breast fleshing score was 0.2 greater in the EG20 compared to EG0. The number of juvenile primary wing feathers and age at first egg decreased by 0.4 and 0.9 d, respectively, per wk of earlier I2. Advancing I2 resulted in birds with increased carcass fat deposition from 16 to 28 wk of age. Carcass fat was 1.3- to 1.6-fold greater in the EG20 only from 4 to 16 wk of age. Early growth increased mostly pullet muscle and skeletal characteristics whereas advancing I2 advanced sexual maturity and increased carcass fat deposition around sexual maturation time.

Dietary superdosing of phytase positively affects growth, mineral utilization and amino acid availability of channel catfish (Ictalurus punctatus)

The present study investigated the effects of supplementing high levels (superdosing) of dietary phytase on growth performance, mineral utilization and digestibility of amino acids in different regions of the gastrointestinal (GI) tract of fingerling channel catfish. The negative control (NC) diet was formulated with primarily soybean meal as a protein feedstuff which contributed 0.61 % total phosphorus (P) but was deficient in available P at 0.11 % of diet. Five other diets were formulated either with supplemental monocalcium phosphate at 1 % of diet in the positive control (PC), or supplemented with Quantum Blue phytase (AB Vista, Plantation, Florida) at 1000, 2000, 4000, or 8000 phytase units (FTU)/kg of diet. Groups of 20 catfish were each stocked into 24 aquaria operated as a closed, recirculating system with biological and mechanical filtration. All dietary treatments were assigned randomly to quadruplicate aquaria and initially fed at 6 % of total body weight per day. Feed quantities were adjusted weekly after weighing all fish in each aquarium as a group, and feeding levels were maintained close to apparent satiation throughout the 8-week feeding trial. Phytase supplementation significantly (P < 0.05) increased various responses of channel catfish including weight gain, feed efficiency, and protein retention compared to catfish fed the NC diet, resulting in values that were similar to catfish fed the PC diet. Moreover, catfish fed the phytase-supplemented diets had higher bone ash, calcium (Ca), magnesium (Mg), P, manganese (Mn), and zinc (Zn), as well as retention of Ca, Mg, P, iron (Fe), Mn, and Zn in whole-body tissues. Additionally, apparent availability of P from the posterior intestinal region increased with dietary phytase supplementation, with reduced excretion of nitrogen, Ca, Mg, P, copper (Cu), Mn, and Zn observed in comparison to fish fed the NC diet. Apparent digestibility coefficients for many of the indispensable and dispensable amino acids were increased by phytase supplementation, except for histidine, methionine, threonine, and taurine. This improvement in amino acid availability occurred only in the posterior region of the gastrointestinal tract. Channel catfish fed the diet containing 4000 FTU/kg diet had the highest postprandial plasma phosphorus level most of the time, except at 24 h after feeding. Based on these various responses, the optimal dietary phytase dosage was determined to average 5492 FTU/kg diet.