Higher Feed Conversion Rate Research Articles

Lactulose with synergists supplementation improving a health of chicks and reducing the environmental burden in poultry industry.

The study aims to understand the effect of new antibiotic-substituting supplements in feeding chickens of the Hisex Brown cross in industrial conditions. A total of 216 hatched chicks were randomly selected and distributed into Control, Test I, and Test II groups, with 3 replicates of 24 birds in three treatments. At the end of the experiment, BW of T1/T2 birds was higher by 6.12% (p <0.01) and 10.29% (p <0.001) than CON. In comparison with the control hens, T1/T2 birds had a higher feed conversion rate and digestibility of nutrients. The blood indicators of T1/T2 hens exceeded those in control. Prebiotic supplementations were positively influenced in the immune indices of birds. IgA, IgG, IgM increased in groups T1/T2. Similar regularity was found in the natural resistance of chicks fed S1/S2. In the caecum, the Lactobacilli number was higher than in CON by 17.03% (p <0.01) in T1 and by 18.47% (p <0.01)-in T2; Bifidobacteria-by 17.94 (p <0.001) and 19.09% (p <0.01), respectively; at the same time, the number of E. coli decreased by 21.05% (p <0.01) and 24.21% (p <0.01). The concentration of emitted excreta noxious gases decreased: ammonia by 22.40%-24.95% (p <0.01); hydrogen sulfide by 10.67%-16.00% (p <0.01); and mercaptans by 12.90%-17.74% (p <0.05). These findings support the use of lactulose-based supplements as antibiotic alternatives to improve production in poultry farming and to reduce the toxic load on the environment.

Study of some Growth Parameters of Grass Carp Ctenopharyngodon idella V. Cultured in Floating Cages

This study included different densities to obtain a better culture density, three densities were used (16-20-25 fish/m3), 500 fish in the first treatment, 650 fish in the second treatment, 800 fish in the third treatment, and average weights ranged between 100-200 gm. Saudi origin diet was used. The experiment was conducted in Thi Qar Governorate, city of Nasiriyah on one of the private farms on the Euphrates River, in which grass carp was farmed. Fish samples were collected monthly from 8/11/2022 to 8/4/2023. Air and water temperatures were also measured during sampling. The air temperature varied between 11-29 C, the water temperature ranged between 9-25 C. The results showed the highest weight gain (17.333, 12.000 and 29.331) during April for all treatments. The results showed that there were significant differences (P≤0.05). In January, there was no significant difference for all treatments, as for the rest of the months, a significant difference (P≤0.05) between the three treatments and the studied densities. The highest qualitative growth rate was recorded in T1 (10.170 gm/fish), T2 (8.193 gm/fish), and T3 (9.186 gm/fish), there were no significant differences in December and March for the three treatments, at the rest of the months, there were significant differences between the three studied treatments at the level (P≤0.05, P≤0.01). The relative growth rate recorded the highest concentrations (22.940, 10.460 and 16.820 gm/fish), T1 during the months of January, February, March and April outperformed the rest of the transactions, At December, T2 outperformed compare others. The results showed that there were significant differences in the three treatments (P≤0.05) during April, as for the rest of the months and for all treatments. The highest feed conversion rate was recorded in T3 at February (25,000 feed/gm), T1 at January (17,000 feed/gm) and T2 at February (8,093 feed/gm). There was no significant difference for the three treatments in December, February and March, but in January and April significant differences were recorded at the level (P≤0.05, P≤0.01). The highest feed conversion efficiency rate (97.733, 39.996 and 57.773%) was recorded in March for the three treatments. There were no significant differences in December and for all treatments, as for the rest of the months and for all treatments, there were significant differences (P≤0.05). The results of the current study showed the superiority of the first treatment in most of the growth criteria over the rest of the treatments. The chemical analysis of fish muscles showed that, at the beginning of the experiment and at the end of the experiment, there were slight changes in the elements of the chemical analysis at the end of the experiment compared to the beginning of the experiment.

Effects of dietary zinc levels on growth, intestinal health, antioxidant and non-specific immunity of spotted seabass (Lateolabrax maculatus) reared at two temperatures

This study investigated effects of dietary zinc levels and water temperature on growth, feed utilization, intestinal health, antioxidant and non-specific immunity of spotted seabass. Six experimental diets were formulated to contain 30, 53, 77, 98, 116, or 145 mg Zn/kg. Each diet was fed to two different groups of fish reared at low temperature (27 °C; LT) or high temperature (33 °C; HT). Triplicate groups of fish were fed the test diets to apparent satiation two times daily for 8 weeks. Results showed that fish under HT showed the lower weight gain (WG) and higher feed conversion rate (FCR) comparing to the LT treatment (P < 0.05). Also, the growth and feed utilization were significantly (P < 0.05) influenced by dietary Zn levels and broken-line regression analysis showed the optimal dietary Zn level for spotted seabass reared at 27 °C and 33 °C are 77.69 mg/kg and 93.61 mg/kg, respectively. Apparent digestibility coefficients (ADCs) of protein and lipid in HT treatment were significantly lower than those of LT treatment (P < 0.05), and ADCs significantly increased with the increase of dietary Zn levels. The histology showed HT and Zn-deficiency can cause the damage of intestine, while fish fed 77 mg Zn/kg diets presented normal structure. Serum LZM activity, C3 and IgM contents of HT treatments were lower than those of the LT treatments. Further, LZM activity, C3, and IgM contents can be significantly elevated by the increasing of dietary Zn levels. MDA content of HT treatments were significantly higher than that of LT treatments, while MDA content decreased with the increase of dietary Zn levels as SOD activity and T-AOC increased. Overall, the optimum dietary Zn level alleviated heat stress via enhancing immunity, antioxidant capacity and intestine health.

Comparative analysis of productive performance and fattening efficiency of commercial pigs in China for two consecutive years

The purpose of this study: (1) propose an evaluation indicator of the fattening efficiency of commercial pigs (Yorkshire × Landrace × Duroc)—fattening efficiency index (FEI). (2) Analyze the correlation to find the main productive factors affecting the FEI. (3) Compare and analyze the yearly/monthly/different piglets’ sources of productive performance in 2020 and 2021. The data included 2592 commercial pig batches in 2020 and 3266 in 2021, with a total of 6,134,234 commercial pigs. Descriptive statistics and difference analysis were carried out on 16 productive factors of a whole year and single/multiple sources for two consecutive years. The same period difference between the monthly data and the annual average were also analyzed. The top six productive factors correlated with FEI were average daily gain (ADG) (0.8080), feed conversion rate (FCR) (− 0.7203), survival rate (SR) (0.6968), number of deaths (− 0.4103), feeding days (− 0.3748) and body weight (BW) of marketing pigs (0.3369). The overall productive performance in 2021 was lower than that in 2020, which was reflected in more piglet sources and a lower BW of piglets, more deaths, a lower SR, longer feeding days, a lower ADG, a higher FCR and a lower FEI. The productive performance of a single source was better than that of multiple ones. The contrastive results of monthly data in 2020 and 2021 showed significant differences in most factors except for the number of marketing pigs, the number of piglets and feed consumption. The monthly trend of 15 factors for two consecutive years revealed similar trends only in the month of piglets purchasing, number of piglets sources, number of deaths and ADG. Compared with the annual average, the ADG significantly increased in May. The FEI of multiple sources was markedly lower than that of a single source. FEI may be suitable for evaluating the fattening efficiency of commercial pigs. The annual and monthly productive performance and fattening efficiency in 2021 were significantly lower than those in 2020. Single source was represented better productive performance and fattening efficiency than multiple ones.

Effects of Iron and Vitamin C on Growth Performance, Iron Utilization, Antioxidant Capacity, Nonspecific Immunity, and Disease Resistance to Aeromonas hydrophila in Chinese Mitten Crab (Eriocheir sinensis)

Iron is an essential trace element with an abroad physiological function, and iron deficiency can impair animal health. Vitamin C (VC) has the potential to release iron from diets and increase iron uptake. This study evaluates the effects of dietary iron and vitamin C on the growth performance, iron utilization, antioxidant capacity, and nonspecific immunity of the Chinese mitten crab (Eriocheir sinensis). Juvenile E. sinensis ( 1.14 ± 0.01 g ) were fed six diets supplemented with three levels of iron (41.40, 92.25, and 143.00 mg/kg), and each iron level supplemented either 4.33 mg/kg or 700.90 mg/kg of vitamin C for 8 weeks. Crabs fed 41.40 mg/kg of iron diet had the lowest weight gain (WG) and specific growth rate (SGR) and had the highest feed conversion rate (FCR) regardless of dietary vitamin C levels. Dietary 700.90 mg/kg of vitamin C improved WG and SGR but decreased FCR when the diets were supplemented with 41.40 and 143.00 mg/kg of iron ( P &lt; 0.05 ). Dietary 700.90 mg/kg of vitamin C significantly improved the expression levels of divalent metal ion transporter 1, ferroportin, and iron regulation protein in the intestine and hepatopancreas when supplemented with 92.25 and 143.00 mg/kg of iron ( P &lt; 0.05 ) and enhanced the transferrin content in hemolymph and iron deposition in the hepatopancreas when supplemented with 92.25 and 143.00 mg/kg of iron ( P &lt; 0.05 ). Crabs fed the diet supplemented with 41.40 mg/kg of iron had the highest malondialdehyde content and the lowest superoxide dismutase activity in the hepatopancreas. Dietary 700.90 mg/kg of vitamin C supplementation also increased the acid phosphatase and bacteriolytic activity when diets were supplemented with 41.40 and 143.00 mg/kg of iron ( P &lt; 0.05 ). In addition, crabs fed 143.00 mg/kg of iron and 700.90 mg/kg of vitamin C diet had the highest survival rate after the Aeromonas hydrophila challenge. This study demonstrates that dietary 700.90 mg/kg of vitamin C could promote iron absorption and utilization, thereby increasing the growth, immunity, and disease resistance of E. sinensis.

The Evaluation of Different Feeds on Brine Shrimp, Artemia parthenogenetica Culture

In this study, Artemia parthenogenetica was fed with either Spirulina (S), yeast (Y), rice bran (R), oat (O) or their combinations in 10 experimental groups in triplicate for 20 days in laboratory conditions and growth, biomass, feed conversion rate (FCR), specific growth rate (SGR), survival rate, crude protein, crude lipid contents were determined. The highest average body length obtained at the end of the experiment was 2.805±0.003 mm in treatments (S) and (SYR), and the highest average individual dry weight was 23.057 µg in treatment (S). The mean biomass changed between 167.2±0.003 mg and 115.7±0.012 mg. The highest biomass value was 20.9 g/m3 in treatment (S), followed by 20.5 g/m3 in treatment (SYR). The highest FCR was found to be similar in (S) and (Y) with 1.14±0.02. SGR was 1.01±0.001 in all experimental groups. The highest survival rate was in treatment (S), and overall it ranged between 78.22±1.78 - 90.64±0.06%. The highest crude protein contents of Artemia were found in (SR) and (S) and the highest lipid content was found in treatment (O). As a result, it is thought that combinations of by-products such as rice bran and yeast together with microalgae will be economical in the cultivation of Artemia parthenogenetica.

Supplementation of Paraformic Acid as a Substitute for Antibiotics in the Diet Improves Growth Performance and Liver Health in Broiler Chickens.

Simple SummaryParaformic acid (PFA) is a hyperpolymer formed by polymerization of formic acid monomers, and PFA has a lower pungent smell and corrosiveness to the gastrointestinal tract compared with formic acid. The liver is a crucial metabolic organ, playing a momentous role in nutrients biosynthesis and metabolism, defense against bacterial invasion, and endotoxin clearance. However, in the condition of intensive poultry husbandry, the broiler’s liver is susceptible to inflammatory damage. Our results showed that PFA supplemented to the diet improved growth performance, inhibited inflammatory response, and benefited liver protection, which provided a direction for the use of PFA in broiler production.The current study aimed to explore the effects of supplementing paraformic acid (PFA) into broilers’ diet on growth performance, inflammatory responses, and liver protection. A total of 567 healthy one-day-old broilers were used in a 42-d study, and they were randomized into three groups. Broilers were fed a basal diet (CON group) or the basal diet supplemented with either 50 mg/kg aureomycin (AB group) or 1000 mg/kg PFA (PFA group). The results showed that the PFA and AB groups had a higher feed conversion rate than the CON group from day 21 to 42 (p < 0.05). Dietary PFA or aureomycin supplementation decreased serum levels of interleukin (IL)-1β, IL-6, IL-10, alanine transaminase, diamine oxidase, and D-lactate, and significantly increased serum concentrations of immunoglobulin (Ig) A, IgM, and complement C4 (p < 0.05). Moreover, dietary PFA or aureomycin supplementation decreased hepatic levels of caspase-1, NOD-like receptor family pyrin domain containing 3 (NLRP3), tumor necrosis factor-alpha, IL-6, and IL-18, as well as NF-κB mRNA expression (p < 0.05). Above all, PFA supplementation into the broilers’ diet improved growth performance, inhibited inflammatory responses, and benefited liver protection. The protective effects of PFA on the liver might be related to inhibition of caspase-1-induced pyroptosis via inactivating the NF-κB/NLRP3 inflammasome axis in broiler chickens.

Nutritional Evaluation of Black Soldier Fly Frass as an Ingredient in Florida Pompano (Trachinotus carolinus L.) Diets.

Simple SummaryCarnivorous fish species, such as the Florida pompano, currently require expensive and unsustainable feed in order to be raised in an aquaculture setting. A waste product of the black soldier fly, frass has the potential to be an alternative carbohydrate source for these fish. This study aims to assess the potential of frass to mimic the growth, body, composition, and intestinal microbiome of pompano that can be achieved through commercial feed. Three diets with varying frass levels as well as a control diet were developed. The frass was found to increase the visceral somatic index and lower the hepatosomatic index. The frass did not alter the body composition or improve the growth performance, leading to a lower specific growth rate and higher feed conversion rate. The microbiome analysis showed the highest diversity of the gut flora in the control diet, while the frass diets showed signs of community imbalance. This may have been due to the decreased starch in the frass, which is usually metabolized by those microbial communities. Overall, frass diets are not ideal for carnivorous fish diets, but have could have potential for feed replacement in herbivore and detritivore fish species.The aquaculture industry is in need of sustainable fish feed to reduce the use of expensive and environmentally invasive wild-caught fish currently fed to many carnivorous species. The black soldier fly (BSF) has become a popular sustainable alternative protein source; however, the nutritional waste byproduct of BSF, frass, has not been extensively studied as a feed replacement in carnivorous species. This study evaluates the potential of BSF frass on the growth, body composition, and intestinal microbiome of the Florida pompano, Trachinotus carolinus. Four experimental diets were formulated containing different levels of frass, replacing plant-based carbohydrate sources. As a result of this study, the frass did not improve the growth performance, resulting in a lower specific growth rate and higher feed conversion rate. While the frass diets did not alter the body composition, the visceral somatic index (VSI) significantly increased compared to the control diet and the hepatosomatic index (HIS) was lowered. The microbiome analysis showed high variation among the diets, with the control diet having the most distinct consortia, which may have been driven by the increased levels of starch compared to frass diets. This study indicates that BSF frass may not be a suitable feed replacement for carnivorous pompano; however, frass could still potentially be a replacement feed for herbivore or detritivore fish and should be further studied.

Carcass Composition and Quality of Meat of Pulawska and Pulawska x PLW Crossbred Pigs Fed Rations with Naked Oats.

Simple SummaryDue to the presence of fibrous hulls, the use of traditional cultivars of oats (Avena sativa L.) in feed rations for pigs is restricted. The development of naked oat cultivars (Avena nuda L.) containing only about 2% of crude fibre allowed this cereal grain to be included in the diets of monogastric animals. The present studies evaluated the efficiency of a 60% inclusion of naked oats in rations fed to Pulawska pigs and Pulawska x Polish Large White (PLW) crossbreds on their performance results (weight gain, feed conversion), carcass composition and physical (pH, colour, WHC) and chemical (essential nutrients, fatty acids) characteristics of meat. It was demonstrated that a 60% inclusion of naked oats is recommended in the diets of Pulawska pigs and Pulawska x PLW crossbreds to maintain carcass composition and meat quality comparable to that of pigs fed with rations containing barley only. The performance indicators of Pulawska pigs declined, but their meat quality traits improved in terms of nutritional value, as the n-6/n-3 acids’ ratio was narrower than that of Pulawska x PLW.The study aimed to determine the impact of a 60% inclusion of naked oats in feed rations for Pulawska pigs and Pulawska x Polish Large White (PLW) crossbreds on the fattening performance, carcass composition, and meat quality. It was demonstrated that—independent from their diet—Pulawska pigs showed a daily weight gain about 14.5% lower (p ≤ 0.05), with about 15% higher feed conversion rate. The experimental factors showed no impact on the dressing percentage, meatiness, and backfat thickness, except that the “eye” of the loin was significantly smaller (by 4.55 cm2) in Pulawska pigs. There was no interaction effect (diet/breed) for the pigs’ performance results and carcass composition. A 60% inclusion of naked oats in the pigs’ diet did not affect the weight of primal cuts in the right-side half-carcass. Compared to Pulawska pigs, crossbreds featured a significantly lower weight of bacon and ribs (by 1.17 kg) but a higher (p ≤ 0.05) weight of fillet (by 1.0 kg) and ham with shin (by 0.43 kg). The diet had no impact on the evaluated muscles, except a reduction (by 2.3 points) in colour lightness (L) of musculus semimembranosus in fattening pigs receiving feed rations with a 60% share of oats. Both muscles in Pulawska pigs showed significantly better (p ≤ 0.05) water-holding capacity and reduced colour lightness (L) in comparison to crossbred pigs. Moreover, the longissimus lumborum muscle of Pulawska pigs had a higher chroma (C) and a lower hue (H). The contents of essential nutrients in the evaluated muscles did not depend on the pigs’ diet and breed, except that a higher by 0.3% (p ≤ 0.05) intramuscular fat content was found in the longissimus lumborum muscle of Pulawska pigs. Neither of the experimental factors showed significant impact on the total saturated fatty acids (SFA) and total unsaturated fatty acids (UFA), or on neutral or hypocholesterolemic (DFA) and hypercholesterolemic fatty acids (OFA) in the evaluated muscles. The muscles of Pulawska x PLW pigs contained more (by 1.77% FA in the longissimus lumborum and 1.16% in the semimembranosus) polyunsaturated fatty acids (PUFA) than the muscles of the Pulawska breed (p ≤ 0.05). In addition, naked oats included in the pigs’ diet increased (p ≤ 0.05) the share of PUFA in intramuscular fat. The muscles of Pulawska pigs, in comparison to the muscles of crossbreds, showed a significantly improved ratio: by 66% and 69% in the longissimus lumborum and the semimembranosus muscles, respectively. To sum up, a 60% inclusion of naked oats is recommended in the rations of both Pulawska pigs and Pulawska x PLW crossbreds, since it allows satisfactory carcass composition and meat quality to be maintained. Pulawska pigs had worse productivity ratios but showed improved meat quality traits in terms of the n-6/n-3 ratio.

Proximate analysis of nutrients and in vitro radical scavenging efficacy in selected medicinal plant powders with potential for use as poultry feed additives

The use of antibiotic feed additives in poultry feed is currently discouraged owing to the development of antibiotic-resistant bacteria and other drawbacks. The benefits and importance of phytogenic feed additives as potential alternatives in poultry nutrition include stimulation of digestion, higher feed conversion rate, reduced incidence of disease and profitability. Evaluation of the mineral content and other properties of plant material generates useful information towards rationalizing the use of plants as alternatives to antibiotic feed additives. Concentrations of macro-and micro-minerals in Morinda lucida, Acalypha wilkesiana, Ficus exasperata and standard broiler feed were determined using ICP-MS, and ICP-OES. Levels of degradation of C and N over specific periods of time were evaluated by dry oxidation (Dumas). Radical scavenging activities were investigated using DPPH and ABTS assays while levels of phytochemical constituents were assessed using standard methods. Macro- and micronutrient concentrations in the plant powders were generally higher than those of standard broiler feed. With few exceptions it was observed that the levels of total C and N as well as the C/N ratio in plant powders and standard feed were proportional to storage time. Macronutrients were higher in F. exasperata and A. wilkesiana while micronutrients were higher in A. wilkesiana and M. lucida. The highest total N and C levels were observed in M. lucida while A. wilkesiana showed the highest C/N ratio. Remarkable radical scavenging activities were displayed by A. wilkesiana while the highest total phenolic content (TPC) and total flavonoid content (TFC) were exhibited by aqueous and acetone extracts of F. exasperata respectively. High antioxidant activity was correlated with high total C and C/N ratio of the plant powders. In M. lucida leaf powder, fructose was the dominant sugar at 8,450 mg/kg DW followed by glucose and sucrose with a good amount of Se at 0.32 mg/kg DW. The contents of malic acid were the highest (20,500 mg/kg DW). Organic acids decrease intestinal Escherichia coli and Salmonella species in broilers. Cl− was the most predominant anion. Minerals and organic acids are essential antimicrobial and antioxidant constituents of poultry diets for the maintenance of gut flora health, and their body metabolic, enzymatic and antioxidant defence. This study highlights the nutrients content of the selected plants, providing motivation for further investigation of these species as poultry feed additives.

Dietary fermented rapeseed or/and soybean meal additives on performance and intestinal health of piglets

The aim of the study was to assess the effect of fermented dried soybean (FSBM) and/or fermented rapeseed meal (FRSM) in diets for weaned piglets on production results, nutrient digestibility, gastrointestinal tract histology, and the composition of the gut microbiota. Piglets in the control group received standard diets with soybean meal. Animals in all experimental groups received diets in which a portion of the soybean meal was replaced: in group FR—8% FRSM; in group FR/FS—6% FRSM and 2% FSBM; in group FS/FR—2% FRSM and 6% FSBM and in group FS—8% FSBM. The use of 8% FRSM or 6% FRSM and 2% FSBM in the piglet diets had a positive effect on average daily gains. Piglets from the FR and FR/FS groups had the highest feed conversion rate. Group FS/FR and FS piglets had significantly lower mortality and lower incidence of diarrhoea. Piglets fed a diet with the fermented components, in particular with 8% FRSM or 6% FRSM and 2% FSBM, exhibited a positive effect on the microbiological composition and histology of intestines, which resulted in improved nutrient digestibility coefficients (ATTD and AID).

Dietary four different woody forages differentially affect the growth, feed utilization, apparent digestibility, intestinal morphology and microbiota composition in Nile tilapia (Oreochromis niloticus)

Woody forage as potential aquatic feed ingredient has a positive effect on tilapia survival and feed utilization. To study the effect of woody forages on the growth, feed utilization, apparent digestibility, intestinal morphology and microbiota composition of Nile tilapia (Oreochromis niloticus), the diets of Moringa oleifera Lam (MOL), Folium mori (FM), Broussonetia papyrifera (BP) and Neolamarckia cadamba (NC) formulated with 70 % of reference (Ref) diet and 30 % corresponding woody leaves were fed to Nile tilapia (12.0 ± 1.0 g) for 55 days, respectively. Results showed that the tilapia dietary MOL had a significant highest final body weight (FBW), weight gain (WG) and lowest feed conversion rate (FCR), while the tilapia dietary NC had a lowest FBW, WG and highest FCR. Although no significant difference in enzyme activities was found among each groups, the enzyme activities (gastric protease and foregut lipase) of tilapia dietary MOL and FM were higher compared with BP and NC. Moreover, the tilapia dietary BP got a significantly highest apparent digestibility (dry matter, crude protein and crude fat) compared with others. Furthermore, the thickness of the muscular layer in foregut and hindgut were significantly decreased in tilapia dietary MOL and increased in tilapia dietary NC. In addition, a much more number of bacterial operational taxonomic units (OTUs) and specialized gut bacterial community were found in tilapia dietary MOL, FM, BP and NC compared with Ref. In conclusion, woody forages (MOL, FM and BP) can be used as potential aquatic feed ingredients without negative effects on growth and intestinal health in Nile tilapia. Adding 30 % MOL to the diet could bring a positive influence on growth, feed utilization and microbiota composition of Nile tilapia, while adding 30 % NC brought negative influence.

Dietary lipid concentrations influence growth, body composition, morphology of the liver and mid-intestine, and antioxidant status of marbled eel (Anguilla marmorata)

An 8-week feeding trial was conducted to explore the effect of dietary lipid concentrations on growth, body composition, morphology of liver, and mid-intestine and antioxidant status in marbled eel (Anguilla marmorata). Fish (initial average weight 6.86 ± 0.11 g) were held in 18 tanks (inside diameter 80 cm, height 60 cm, volume 300 L, 25 fish/tank), with triplicate treatment groups being fed to apparent satiation twice each day on isonitrogenous (421 g/kg crude protein) diets containing different concentrations of lipid (41.2, 73.9, 113.9, 146.2, 178.1, and 216.7 g/kg). The sampling procedure was implemented after 24 h of fasting. Fish fed the diets with 178.1 and 216.7 g lipid/kg grew better than fish fed the other diets. The lowest feed intake and the highest feed conversion rate were found in 41.2 g/kg group. Muscle lipid concentrations and heights of intestinal folds, enterocytes, and microvilli in mid-intestine increased as dietary lipid concentrations increased from 41.2 to 178.1 g/kg. Hepatocyte hypertrophy and lipid vacuolization were seen in liver of the fish fed 216.7 g/kg diet. Based on broken-line analysis of serum total antioxidant capacity and quadratic regression analysis of serum glutathione peroxidase and catalase, it was concluded that dietary lipid concentrations of 125.5–159.2 g/kg promoted antioxidant status. A broken-line analysis of data for specific growth rate and weight gain gave an estimated optimal dietary lipid concentration of 195.3–198.7 g/kg. Marbled eel had quite a high demand for dietary lipid to support good growth, but excessive lipid level (216.7 g/kg) may have an adverse impact on liver structure. Moreover, marbled eel may not tolerate high concentration of dietary carbohydrate.

GENE CONSERVATION PRACTICE AND PRODUCTION OF OLD HUNGARIAN GOOSE BREEDS

Hungarian goose production and gene conservation practices have been a tradition in Hungary for several centuries. The old Hungarian geese can only be effectively maintained if the national programs can identify economic uses of the breed. This study aimed to examine the potential use of the Hungarian landrace goose (HL) either as a purebred or crossbred with the Hungarian Upgraded breed (HU). Crossbred offspring were produced by HL ganders and HU layers, as egg production of HL layers is very low. Reproduction traits (egg production, fertility and hatchability) of parent stocks, body weight gain, feed consumption and slaughter values (slaughter loss, breast and thigh weight and proportions) and of offspring were measured. The results showed that fertility in the crossbred geese was insignificant compared to the fertility of HL purebreds, while hatchability of crossbreds was higher than that of purebred HL or HU. HL offspring had significantly lower bodyweight and weight gain, and a higher feed conversion rate than HU. The proportion of valuable meat parts (breast and thigh) was the highest in HU while weight in slaughter loss was also the highest in HU. In terms of body weight, feed conversion rate and slaughter properties, crossbred offspring showed intermediate inheritance. HL is recommended for crossbreeding with HU breeds and their offspring should be reared under free-range keeping conditions.

Comparison of culture performance and gonadal development of wild-caught Chinese mitten crab Eriocheir sinensis juveniles from three major river populations

The Chinese mitten crab Eriocheir sinensis is an important aquaculture species in China, the main culture locations of which are the river basins of the Liaohe, Huanghe and Yangtze Rivers. This study was conducted to compare culture performance and gonadal development of wild E. sinensis populations from the three rivers cultured in identical ponds. In both females and males, the Yangtze population (YP) had a significantly (P < 0.05) higher mean body weight, weight gain rate (WGR) and specific growth rate (SGR) than the Liaohe population (LP) from March to May and July–September, and the LP had the highest WGR and SGR from May to July. The onset of molting during puberty and gonad development were earliest in the LP; the gonadosomatic index of the Huanghe population (HP) was between that of the YP and LP. In terms of size distribution, YP and LP had the most large-sized and small-sized individuals, respectively. YP had the highest yield and lowest feed conversion rate (FCR), and HP had the lowest survival and highest FCR. In conclusion, the YP showed the best culture performance of the three populations. Each population completed puberty molting and gonadal development at a different time, therefore selective breeding could extend the time to market of this crab.

Rearing, bird type and pre-slaughter transport conditions of broilers II. Effect on foot-pad dermatitis and carcass quality

A multivariable linear model was used to analyse the incidence of carcass quality defects over one year in a commercial database that included 1,856 flocks of Ross broilers (9,188 shipments, 1,975,420 carcasses inspected). The incidence of foot-pad dermatitis (FPD), scratches and wing and back haematomas was scored and analysed in terms of the effects of transport distance, arrival time to the slaughterhouse, waiting time at the slaughterhouse, maximum outside temperature on the day of transport, feed conversion rate, stocking density, bird type (yellow-skinned females or males, white-skinned females or males and roaster females), thinning (birds transported after thinning, birds remaining after thinning, and non-thinned flocks), bed litter type (rice hulls, chopped straw or wood shavings), and ventilation system (dynamic, static or tunnel). The incidence of FPD was significantly (p&lt;0.001) lower at higher maximum temperatures and higher in flocks with a higher feed conversion rate. FPD also increased with stocking density (kg/m2) and was, on average, 5.0% higher in males than females. Regarding thinning, FPD was 13% lower in birds transported after thinning. Birds raised on chopped straw had more FPD (49.3%), followed by wood shavings (31.1%). Scratches were higher at higher temperatures and increased with transport distance. Birds transported after thinning had 5.8% more scratches than non-thinned birds, while increased stocking density (kg/m2) on the farm tended to increase scratches. Back haematomas were 32.6% higher in birds that were thinned, while wing haematomas increased with stocking density (kg/m2). Back haematomas were also 23.7% higher in males and more common in white-skinned birds.

Use of seaweed Ulva lactuca for water bioremediation and as feed additive for white shrimp Litopenaeus vannamei.

Two experimental feeding trials were conducted during four weeks to evaluate the use of Ulva lactuca in shrimp culture: (1) for wastewater bioremediation, and (2) using different inclusion levels of U. lactuca meal in shrimp feed. In feeding trial 1, shrimp reared under seaweed U. lactuca water exchange in a re-circulation system (SWE) resulted in similar growth and feed utilization as shrimp reared with clean water exchange (CWE). Shrimp under no water exchange (NWE) resulted in significant lower growth and higher feed conversion rate (FCR) compared to the other treatments (p < 0.05). Nitrogen compounds and phosphate in water from SWE and CWE treatments did not present significant differences during the experimental trial (p > 0.05). In feeding trial 2, U. lactuca biomass produced by wastewater bioremediation in SWE treatment were dried and ground to formulate diets containing 0, 1, 2, and 3% U. lactuca meal (0UL, 1UL, 2UL, and 3UL). Shrimp fed the 3 UL diet resulted in a significant (p < 0.05) improvement of growth and FCR, and enhanced whole shrimp lipid and carotenoid content by 30 and 60%, respectively, compared to control diet. Seaweed U. lactuca is suggested as a desirable species for wastewater bioremediation in integrated aquaculture systems, and its meal as a good feed additive for farmed shrimp.

Effects of dietary manganese source and supplemental levels on growth performance, antioxidant enzymes activities, tissue Mn concentrations and cytosolic manganese superoxide dismutase (cMnSOD) mRNA expression level of juvenile Litopenaeus vannamei

This experiment was conducted to study the effects of different forms and levels of manganese (Mn) on the growth performance, antioxidant activities, tissue Mn content and cytosolic manganese superoxide dismutase (cMnSOD) gene expression of Litopenaeus vannamei. Treatments consisted of 0, 10, 20, 30, 40 and 60 mg Mn kg−1 from manganese sulphate (Mn-S) and manganese methionine (Mn-Met), providing the actual dietary value of 5.17, 15.62, 25.55, 34.22, 44.48 and 67.90 mg Mn kg−1 Mn-S, and 5.17, 15.71, 25.36, 35.86, 45.16 and 65.06 mg Mn kg−1 Mn-Met, respectively. Each diet was fed to triplicate groups of L. vannamei (initial body weight: 1.925 ± 0.002 g) in a recirculated fresh water rearing system for 8 weeks. Weight gain rate (WGR) increased in prawns provided with from 25.55 to 44.48 mg Mn kg−1 Mn-S and 15.71 to 45.16 mg Mn kg−1 Mn-Met and then declined above these levels. The lowest protein efficiency ratio (PER) and the highest feed conversion rate (FCR) were observed in prawns fed the control diet (P 0.05). Survival rate (SR) was not affected by the dietary treatments (P > 0.05). Total SOD and Mn-SOD activities were higher in the hepatopancreas of prawns fed with Mn-supplemented diets from 15.71 to 44.48 mg Mn kg−1 (P < 0.05). On the contrary, malondialdehyde (MDA) content was lower in the hepatopancreas of prawns fed the basal diet (P < 0.05). Mn concentrations in the hepatopancreas and muscles increased with increasing levels of dietary Mn supplementation. Moreover, Mn accumulation was lower in the muscle than in the hepatopancreas of the prawns. The mRNA expression of cMnSOD gene in the hepatopancreas of prawns was upregulated with increasing dietary Mn levels of Mn-S from 25.55 to 44.48 mg Mn kg−1, Mn-Met from 15.71 to 45.16 mg Mn kg−1 and then plateaued above these levels. Broken-line regression analysis of WGR indicated that the optimal dietary Mn requirements for juvenile L. vannamei were 32.26 mg Mn kg−1 Mn-S and 23.90 mg Mn kg−1 Mn-Met, respectively.

Effects of Dietary Alpha-lipoic Acid and Acetyl-L-carnitine on Growth Performance and Meat Quality in Arbor Acres Broilers.

An experiment was conducted to evaluate the effects of dietary alpha-lipoic acid (LA) and acetyl-L-carnitine (ALC) on growth performance, carcass characteristics and meat quality in Arbor Acres broilers. A total of 486 1-d-old male Arbor Acres broilers were randomly allocated to 9 dietary treatments, 9 treatments were group A (0 mg/kg LA and 0 mg/kg ALC), group B (50 mg/kg LA and 0 mg/kg ALC), group C (100 mg/kg LA and 0 mg/kg ALC), group D (0 mg/kg LA and 50 mg/kg ALC), group E (50 mg/kg LA and 50 mg/kg ALC), group F (100 mg/kg LA and 50 mg/kg ALC), group G (0 mg/kg LA and 100 mg/kg ALC), group H (50 mg/kg LA and 100 mg/kg ALC), group I (100 mg/kg LA and 100 mg/kg ALC). Birds were slaughtered at 42 days old. Average daily gain (ADG), average feed intake (AFI), feed conversion rate (FCR), eviscerated rate, breast muscle percentage, thigh muscle percentage, abdominal fat percentage, liver weight, muscle color (L* value, a* value, b* value), pH values at 45 min and 24 h postmortem were measured. Results showed that there existed an interaction between LA and ALC in growth performance of broilers, carcass traits and meat quality. The overall result is that high level of LA and ALC led to lower AFI, ADG (p<0.01), lower abdominal fat percentage, liver weight (p<0.01), lower L* value, a* value, and b* value of breast muscle, L* value of thigh muscle (p<0.05), and higher FCR (p<0.01), eviscerated rate (p<0.01), breast muscle percentage, thigh muscle percentage (p<0.05), a* value, pH 45 min and pH 24 h of thigh muscle (p<0.01). These results suggested that dietary LA and ALC contributed to the improvement of meat quality in broilers.

Amino acids modulates the intestinal proteome associated with immune and stress response in weaning pig

The objective of this study was to investigate the effects of free amino acids supplementation to protein restricted diet on the intestinal morphology and proteome composition in weaning pigs. Weanling piglets were randomly fed one of the three diets including a corn-soybean based control diet and two lower protein diets with or without free amino acids supplementation for 2 weeks. The jejunum samples of piglets were collected for morphology and proteome analysis. Compared with the control diet, the protein restricted diet had a significant lower average daily gain and higher feed conversion rate. Free amino acids supplementation to the protein restricted diet significantly improved average daily gain and higher feed conversion rate, compared with the protein restricted diet. The villous height in pigs fed the protein restricted diet was lower than that of the control and free amino acids diet. Using two-dimensional gel electrophoresis and mass spectrometry, we identified 16 differentially expressed protein spots in the jejunum of the weaning piglet. These proteins were related to stress and immune response, the metabolism of carbohydrates and lipids, and tissue structure. Based on the proteome and ELISA analysis, free amino acids diet significantly down-regulated the jejunal expression of stress protein heat shock 60 kDa protein. Our results indicated that amino acids supplementation to the protein restricted diet could enhance weight gain and feed efficiency in weanling pigs through improving intestinal nutrient absorption and transportation, gut health, and mucosal immunity.