Apparent and standardized ileal digestibility of amino acids in diverse barley cultivars fed to growing pigs

The objectives of this study were to determine the chemical composition, ileal amino acid (AA) digestibility of barley varieties and to develop equations to predict the AA digestibility based on the chemical characteristics of individual barley. A wide selection of nine barley varieties in the main growing regions of China was used in the experiment. Ten crossbred pigs (30.9 ± 1.8 kg) were allotted to a 6 × 10 Youden Square. The treatments included a nitrogen‐free diet and nine barley test diets. Considerable variation was observed in the content of neutral detergent fiber, acid detergent fiber, crude protein (CP) and all AAs among the barley samples. The standardized ileal digestibility (SID) of indispensable AAs with the exception of arginine, phenylalanine and threonine were different (P < 0.05) among the nine barley sources tested. With R² values exceeding 0.50, significant linear regression equations for CP and threonine were obtained. In conclusion, significant differences existed in the ileal digestibility of CP and AAs among barley varieties. It is difficult to predict the SID of most of the amino acids in barely based upon chemical characteristics.     

Effects of Lactobacillus plantarum on the intestinal morphology,intestinal barrier function and microbiota composition of suckling piglets

This study investigated the effect of Lactobacillus plantarum strain 299v on gut health in suckling piglets. Sixty newborn piglets were assigned to control and probiotic treatments, with three litters per treatment (ten piglets/litter). From days 1 to 20 of life, piglets were orally administered a placebo of 0.1% peptone or 1.0 ×  10¹⁰ CFU L. plantarum 299v daily. Six piglets per treatment were sacrificed on day 20, and intestinal tissues (including duodenum, jejunum, ileum and colon) and the intestinal contents from colon segments were collected. The results demonstrated that piglets treated with L. plantarum 299v had a lower diarrhoea incidence than the controls. L. plantarum 299v administration significantly increased the ratio of the villus height to the crypt depth in the jejunum and ileum, as well as the mRNA expression of jejunal occludin and ileal zonula occludens 1 (ZO‐1). The L. plantarum treatment also increased the mRNA abundance of porcine β‐defensin 2 (pBD2) and pBD3 in the jejunum and ileum and of toll‐like receptors (TLRs), such as TLR2, TLR4, TLR6 and TLR9 in the ileum, and significantly upregulated the mRNA abundances of ileal pBD1 and colonic TLR4. Additionally, the L. plantarum 299v treatment significantly changed the structure of the colonic microbiota, as evidenced by the obvious increases in the relative abundances of the phyla Firmicutes and Actinobacteria and of the genus Lactobacillus. Our findings indicate that L. plantarum 299v facilitates the gut health of suckling piglets, probably by improving the intestinal morphology and intestinal barrier function and by modifying the structure of the gut microbiota.     

Rare earth element‐enriched yeast improved egg production and egg quality in laying hens in the late period of peak egg production

The objective of this study was to determine the effects of rare earth element‐enriched yeast (RY) on egg production, coefficient of total tract apparent digestibility (CTTAD), egg quality, excreta gas emission and excreta microbiota of laying hens. A total of 216 ISA brown laying hens of 52 weeks of age were used in a 5‐week feeding trial and data were collected every week. Birds were randomly allotted to three dietary treatments each with six replicates and 12 hens per replicate. Each cage (38 cm width × 50 cm length × 40 cm height) contained one hen. Treatments consisted of corn–soya bean meal‐based diet supplemented with 0, 500 or 1000 mg/kg of RY. From weeks 55 to 56, inclusion of RY linearly increased (p < 0.05) egg production. The CTTAD of nitrogen was increased (linear, p < 0.05) with increasing dietary level of RY. In week 55, yolk height and Haugh units were increased linearly (p < 0.05) with increasing dietary RY content. However, no significant effects were observed in terms of excreta emissions and excreta microbiota in laying hens. In conclusion, dietary supplementation with RY improved egg production and CTTAD of nitrogen and slightly improved egg quality in laying hens of the late period of peak egg production.     

Effects of different levels of sanguinarine on antioxidant indices,immunological responses,ileal microbial counts and jejunal morphology of laying hens fed diets with different levels of crude protein

This study was carried out to assess the effects of different levels of sanguinarine on antioxidant indices, immunological responses, serum biochemical parameters, ileal microbial counts and jejunal morphology of laying hens fed on diets with different levels of crude protein (CP). A total of 180 laying hens were subjected into nine dietary treatments with four cages of five birds each. Experimental treatments consisted of three levels of CP (85.0, 92.5 and 100% of Hy‐Line W36 manual recommendation) and three levels of sanguinarine (0.00, 3.75 and 7.50 mg/kg) as a 3 × 3 factorial arrangement of laying hens which fed during a 70‐day feeding trial. The in vitro study showed that sanguinarine exhibited sevenfold and threefold decreased antioxidant activities to inhibit 2‐2‐diphenyl‐1‐picric hydrazyl free radical as well as ferric ion reducing rather than butylated hydroxyl toluene. Although using the decremental levels of CP caused the increase in heterophil‐to‐lymphocyte ratio (p < 0.01), dietary administration of sanguinarine could suppress the serum cholesterol and malondialdehyde concentrations as well as heterophil‐to‐lymphocyte ratio (p < 0.05). Additionally, decreasing CP content resulted in the decreased percentage of albumin (p < 0.05); however, it had no negative effects on humoral immunity. Nonetheless, feeding of at least 3.75 mg/kg sanguinarine led to the remarkable increases in serum gamma globulin concentration (p < 0.01) and secondary (p < 0.05) antibody titres against sheep red blood cells. Moreover, a decline in dietary CP content led to higher villi height and crypt depth (p < 0.05; p < 0.001) and consequently decreased villi height‐to‐crypt depth ratio (p < 0.001) than the optimum level (100% CP). In spite of the effects of sanguinarine on the suppression of Escherichia coli and Salmonella counts (p < 0.05), it markedly enhanced villi height‐to‐crypt depth ratio as well as lamina propria lymphatic follicles extent, simultaneously (p < 0.001). Therefore, in spite of the detrimental effects of feeding low‐CP diets on lymphocytes and serum albumin percentages, and villi height‐to‐crypt depth ratio, the administration of incremental levels of sanguinarine could improve cellular and humoral immunity, decrease ileal microbial counts and in turn improve the intestinal health indices in laying hens.     

Dietary protein levels and amino acid supplementation patterns alter the composition and functions of colonic microbiota in pigs

Different dietary nitrogen (N) patterns may have different effects on gut microbiota. To investigate the effects of different crude protein (CP) levels or essential amino acids (EAA) supplementation patterns on the structure and functions of colonic microbiota, 42 barrows (25 ± 0.39 kg) were randomly assigned to 7 dietary treatments including: diet 1, a high CP diet with balanced 10 EAA; diet 2, a medium CP diet with approximately 2% decreased CP level from diet 1 and balanced 10 EAA; diets 3, 4, 5, 6 and 7, low CP diets with 4% decreased CP level from diet 1. Specifically, diet 3 was only balanced for Lys, Met, Thr and Trp; diets 4, 5 and 6 were further supplemented with Ile, Val and Ile + Val on the basis of diet 3, respectively; and diet 7 was balanced for 10 EAA. Results over a 110-d trial showed that reducing the CP level by 2% or 4% dramatically decreased N intake and excretion (P < 0.05) in the presence of balanced 10 EAA, which was not observed when altering the EAA supplementation patterns in low CP diet (−4%). With balanced 10 EAA, 2% reduction in dietary CP significantly reduced Firmicutes-to-Bacteroidetes (F:B) ratio and significantly elevated the abundance of Prevotellaceae NK3B31 (P < 0.05); whereas 4% reduction evidently increased the abundances of Proteobacteria, Succinivibrio and Lachnospiraceae XPB1014 (P < 0.05). Among the 5 low CP diets (−4%), supplementation with Ile, or Val + Ile, or balanced 10 EAA increased F:B ratio and the abundance of Proteobacteria. In addition, the predicted functions revealed that different CP levels and EAA balanced patterns dramatically altered the mRNA expression profiles of N-metabolizing genes, the “N and energy metabolism” pathways or the metabolism of some small substances, such as amino acids (AA) and vitamins. Our findings suggested that reducing the dietary CP levels by 2% to 4% with balancing 10 EAA, or only further supplementation with Ile or Val + Ile to a low protein diet (−4%) reduced the N contents entering the hindgut to various degrees, altered the abundances of N-metabolizing bacteria, and improved the abilities of N utilization.     

Micronized fibres affect in vitro fermentation under normal buffered and osmotic stress conditions using porcine inocula

In this in vitro study, the modified Hohenheim gas test was used to determine fermentation activity and bacterial composition of pig's faecal microbial inoculum, when fermenting a standard pig diet with varying levels of crude protein (CP; 20, 24 and 28% CP), and supplemented with one of three fibre sources manufactured by micronization treatment. These were wheat envelopes (MWE), pea fibre (MPF) and lupine fibre (MLF). For comparison, inulin was used. As intestinal bacteria have to cope with varying osmotic conditions in their ecosystem, fermentation was performed under normal buffered and osmotic stress conditions. After 24 h of fermentation, total gas production and ammonia production were measured. In addition, the effect of MWE and inulin on short‐chain fatty acid (SCFA) production and numbers of total eubacteria, Lactobacillus spp., Bifidobacterium spp., Enterobacteriaceae, Enterococcus spp., Clostridium cluster XIVa and Clostridium cluster IV, were determined using quantitative real‐time PCR. Under normal buffered conditions, supplementation of MWE resulted in increased (p < 0.05) SCFA, acetic, propionic and valerianic acid production at CP levels of 20 and 28%. There was an increase (p < 0.05) in ammonia production for the micronized supplements, and for MWE an increased (p < 0.05) branched‐chain proportion was observed, possibly due to higher availability of protein for fermentation which was released during the micronization process. Osmotic stress conditions reduced (p < 0.05) total gas as well as total SCFA, acetic and propionic acid production for all treatments, while cell counts were increased (p < 0.05) for Bifidobacterium spp., Enterococcus spp. and Lactobacillus spp. Under normal buffered conditions in combination with 24 and 28% CP levels, lactobacilli were increased for MWE, compared to inulin (p < 0.05). In conclusion, micronized supplements such as MWE may beneficially modulate pigs' intestinal microbiota by increasing SCFA production in addition to a selective proliferation of lactobacilli.     

The effects of dietary reduced mineral elements and coated cysteamine supplementation on bacterial diversity in the ileum of finishing pigs

This study was conducted to investigate the effects of different levels of dietary partial MEs and coated cysteamine (CC) supplementation on gut microbiota in finishing pigs. Results showed that whittling down dietary partial MEs (Cu, Fe, Zn, Mn) by 20% and 40% had little effect on the microbial diversity, community structure, and bacterial relative abundance in the ileum of finishing pigs. Supplementation with 1,600 mg/kg CC also had no obvious effect on the microbial diversity, community structure, and bacterial relative abundance in the finishing pig ileum when fed diets with a normal MEs level. However, the abundance of Peptostreptococcaceae, Pasteurella, and Pasteurella_aerogenes was higher, and the abundance of Actinobacillus_minor was lower in the 20% ME reduction diet treatment than that in the 20% ME reduction with 1,600 mg/kg CC diet group (p < 0.05). In conclusion, our results suggested that there is no obvious effect on gut microbiota when dietary partial MEs are reduced by 20% or 40%, which indicates the feasibility of reducing dietary partial MEs by 20% or 40% in finishing pigs. Supplementation with CC changed the relative abundance of some bacteria related to opportunistic pathogenicity in the finishing pig ileum when were fed a 20% ME reduction diet.     

Effects of different protein sources completely replacing fish meal in low‐protein diet on growth performance,intestinal digestive physiology,and nitrogen digestion and metabolism in nursery pigs

The study compared the effects of selected proteins replacing fish meal in low‐protein diets on piglets’ growth performance, intestinal digestive physiology, and nitrogen digestion and metabolism. Five reduced CP, amino acid (AA)‐supplemented diets containing 4% of either S50, HP300, concentrated degossypolized cottonseed protein (CDCP), P50, or fish meal were assigned to six pens with 11 pigs for a 28‐day study period. Compared with fish meal, dietary proteins did not affect growth performance, apparent total tract digestibility (ATTD) of nutrients, serum hormone levels and biochemical parameters, apparent ileal digestibility (AID) of CP and most AA, colonic short‐chain fatty acid (SCFA) contents, duodenal and ileal morphology, digestive enzyme activity, and pH in small intestine of piglets. However, HP300, CDCP, and P50 decreased (p < 0.05) fecal N excretion per weight gain. AID of Ile in S50 and HP300 and Glu in P50 were improved (p < 0.05), and AID of Gly in other proteins was reduced (p < 0.05). S50 and P50 lowered (p < 0.05) the contents of colonic isobutyric and isovaleric. S50 and HP300 reduced (p < 0.05) jejunal villus height. CDCP increased (p < 0.05) the pepsin activity in stomach. S50, HP300, and CDCP decreased (p < 0.05) pH in the proximal colon. Overall, the selected proteins could completely replace fish meal in low‐protein diet without impairing piglets’ growth via maintaining intestinal digestive physiology, and nitrogen digestion and metabolism.     

A deficient or an excess of dietary threonine level affects intestinal mucosal integrity and barrier function in broiler chickens

The aim of this study was to investigate the effects of deficient or excess of dietary threonine (Thr) levels on intestinal integrity and barrier function of broilers. A total of 432 1‐day‐old commercial broilers (Arbor Acre) were assigned to four experiment groups consisting of six replicates of 18 birds. The treatments were designed as follows: 85%, 100%, 125% and 150% of NRC (Nutrient requirements of poultry (9th edn). Washington, DC: The National Academies Press, 1994) recommendations. The results indicated that expressions of jejunal and ileal secretory immunoglobulin A (sIgA) mRNA were increased linearly or quadratically by increasing Thr (p < .05), and the highest sIgA mRNA abundance was obtained in 125% Thr level. Likewise, the intestinal sIgA content showed similar increasing trend with the intestinal sIgA gene expression in this instance. The high level of Thr inclusion upregulated mucin 2 (MUC2) mRNA expression in the jejunum and ileum (p < .05). In addition, on day 21, the expression levels of jejunal zonula occludens‐2 (ZO‐2) and ileal zonula occludens‐1 (ZO‐1) decreased then increased with increasing Thr level (p < .05), whereas, the mRNA expressions of occludin in the jejunum and ileum had no significant difference amongst groups (p >.05). On day 42, Thr treatments did not affect the mRNA abundance of measured genes in the jejunum and ileum (p > .05). These findings suggested that Thr might be a nutrient immunomodulator that affects intestinal barrier function, moreover, 125% of the NRC (1994) recommendations Thr level was optimum.     

Effect of organic acids–essential oils blend and oat fiber combination on broiler chicken growth performance,blood parameters,and intestinal health

This study evaluated the effect of organic acids–essential oils blend with or without oat hulls (OH) on growth performance, organ weights, blood parameters, gut morphology, microbiota, and short-chain fatty acids (SCFA) in broiler chickens. Day-old broiler chickens were randomly allocated to 4 dietary treatments consisting of 1) a corn-soybean meal-wheat based diet (BAS), 2) BAS + 0.05% bacitracin methylene disalicylate (BMD), 3) BAS + protected organic acids–essential oils at 300 g/1,000 kg of feed (OE), and 4) BAS + protected organic acids–essential oils at 300 g/1,000 kg of feed + 3% OH (OEOH), in 8 replicate groups. Feeding was in starter (d 0 to 14), grower (d 14 to 24), and finisher (d 24 to 36) phases. Body weight (BW), feed intake (FI), feed conversion ratio (FCR), and mortality were determined weekly. On d 36, 8 chickens per treatment were sampled for blood biochemistry, organ weights, cecal SCFA production, and microbiota. Treatments had no effect on FI and FCR at all phases. Both OE and OEOH treatments reduced (P < 0.001) the body weight gain of birds at the starter phase. Birds fed the OEOH treatment had higher (P < 0.001) gizzard weight, while those offered the BMD diet showed a tendency (P = 0.08) to have higher cecal weight. Birds in the OEOH treatment recorded increased ileal villus height and villus height-to-crypt depth ratio, as well as reduced duodenal crypt depth, while birds in the OE treatment had increased jejunal villus height and villus height-to-crypt depth ratio. Both OEOH and OE treatments increased the number of goblet cells produced in the duodenum and jejunum. Treatments had no effect on SCFA concentrations. Birds in the OE treatment recorded the lowest concentration of blood urea (P = 0.05) and cholesterol (P < 0.05). Both OE and OEOH treatments increased (P < 0.05) the relative abundance of potentially beneficial bacteria in the genus Firmicutes_unclassified, Ruminococcus, Turicibacter, and Erysipelotrichaceae_unclassified, while reducing (P < 0.001) the relative abundance of potentially harmful Coprobacillus. Conclusively, both protected organic acids–essential oils blend and its combination with oat fibers show potential as tools to achieve antibiotics reduction in broiler production.     

Effect of dietary threonine on laying performance and intestinal immunity of laying hens fed low‐crude‐protein diets during the peak production period

Threonine (Thr) may be a limiting amino acid for laying hens fed diets with lowered protein level. An experiment was conducted to examine laying performance, and the intestinal immune function of laying hens provided diets varying in digestible Thr levels. Lohmann Brown laying hens (n = 480), 28 weeks of age, were allocated to six dietary treatments, each of which included five replicates of 16 hens. Dietary crude protein (CP) 16.18% diet was offered as the positive control diet. L‐Thr was added to the negative diet (14.16% CP) by 0, 1.0, 2.0, 3.0 and 4.0 g/kg, corresponding 0.44%, 0.43%, 0.49%, 0.57%, 0.66% and 0.74% digestible Thr. At 40 weeks, a reduction in CP level decreased laying performance (p < 0.05). In the low CP, increasing dietary Thr increased (p < 0.05) egg production and egg mass and rose to a plateau between 0.57% and 0.66%. The hens fed 0.66% Thr showed the lowest value (p < 0.05) of feed conversion ratio (FCR). Serum level of uric acid showed the lowest values (p < 0.05) at 0.57–0.66%. In addition, serum‐free Thr maximized (p < 0.05) between 0.66% and 0.74%. Digestive trypsin activity decreased (p < 0.05) when hens fed the low‐CP diet compared with hens fed CP (16.18%) and hens fed 0.57–0.66%. Expressions of ileal MUC2 mRNA maximized (p < 0.05) at 0.66% Thr. Occludin mRNA increased with increasing Thr level (p < 0.05). sIgA mRNA reached to the maximum level (p < 0.05) at 0.66% and 0.74% Thr. INF‐γ mRNA reached to the lowest level (p < 0.05) at 0.65%. Expressions of ileal IL‐2, IL‐6, IL‐1β mRNA decreased with increasing Thr level (p < 0.05). In conclusion, Thr supplementation resulting in optimal laying performance and stimulated the mucosal immune system, suggesting that it is a limiting amino acid in the low‐crude‐protein diet of laying hens during the peak production period.     

Evaluation of standardized ileal digestible lysine requirement for 8–20 kg pigs fed low crude protein diets

Two experiments were conducted to determine the standardized ileal digestible lysine (SID Lys) requirement for weaned pigs fed with low crude protein (CP) diet. In Experiment 1, 144 pigs were fed a normal CP (20%) diet with 12.3 g/kg SID Lys and five low CP (18.5%) diets providing SID Lys levels of 9.8, 11.1, 12.3, 13.5, and 14.8 g/kg, respectively, for 28 days. Reducing dietary CP from 20% to 18.5% enhanced (p < 0.05) the growth performance. The average daily gain (ADG) and gain to feed ratio (G:F) increased (linear and quadratic; p < 0.05), serum urea nitrogen (SUN) decreased (linear and quadratic; p < 0.05) as SID Lys increased. The SID Lys levels required to maximize ADG and optimize G:F were 12.8 and 13.1 g/kg using a curvilinear plateau model, and to minimize SUN was 13.4 g/kg using a two‐slope broken‐line model, which averaged 13.1 g/kg SID Lys. In Experiment 2, 18 pigs were used in a 12‐day N balance trial and received the same diets of Experiment 1. Total N excretion was decreased when dietary CP reduced and further decreased when SID Lys increased. Collectively, 1.5% dietary CP reduction improved the growth performance and decreased the N excretion; the optimal SID Lys requirement was at 13.1 g/kg of 8–20 kg pigs fed with 18.5% CP diet.     

Intestinal microbiota of broilers submitted to feeding restriction and its relationship to hepatic metabolism and fat mass: Fast‐growing strain

The present study was conducted to verify how feed restriction affects gut microbiota and gene hepatic expression in broiler chickens and how these variables are related to body weight gain. For the experiment, 21‐d‐old Cobb500^TM birds were distributed in a completely randomized experimental design with three treatments: T1. Control (ad libitum—3.176 Mcal/kg ME—metabolizable energy—and 19% CP—crude protein); T2. Energetic restriction (2.224 Mcal/kg ME and 19% CP) from 22 to 42 days with consumption equivalent to control; T3. Quantitative restriction (70% restriction, i.e., restricted broilers ingested only 30% of the quantity consumed by the control group—3.176 Mcal/kg ME and 19% CP) for 7 days, followed by refeeding ad libitum from 28 to 42 days. Ileum and caecum microbiota collections were made at 21, 28 and 42 days of age. Hepatic tissue was collected at 28 and 42 days old for relative gene expression analyses. At 43‐d‐old, body composition was quantified by DXA (Dual‐energy X‐ray Absorptiometry). Both feed restriction programmes decreased Lactobacillus and increased Enterococcus and Enterobacteriaceae counts. No differences were found in the refeeding period. Energetic restriction induced the expression of CPT1‐A (Carnitine palmitoyltransferase 1A) gene, and decreased body fat mass. Quantitative feed restriction increased lipogenic and decreased lipolytic gene expression. In the refeeding period, CPT1‐A gene expression was induced, without changing the broilers body composition. Positive associations were found between BWG (Body Weight Gain) and Lactobacillus and Clostridium cluster IV groups, and negatively associations with Enterobacteriaceae and Enterococcus bacterial groups. In conclusion, differences found in microbiota were similar between the two feed restriction programmes, however, hepatic gene expression differences were only found in quantitative restriction. Higher counts of Lactobacillus and Clostridium cluster IV groups in ileum are likely to be related to better broiler performance and low expression of lipogenic genes.     

Dietary α‐ketoglutarate supplementation improves hepatic and intestinal energy status and anti‐oxidative capacity of Cherry Valley ducks

α‐Ketoglutarate (AKG) is an extensively used dietary supplement in human and animal nutrition. The aim of the present study was to investigate effects of dietary AKG supplementation on the energy status and anti‐oxidative capacity in liver and intestinal mucosa of Cherry Valley ducks. A total of 80 1‐day‐old ducks were randomly assigned into four groups, in which ducks were fed basal diets supplemented with 0% (control), 0.5%, 1.0% and 1.5% AKG, respectively. Graded doses of AKG supplementation linearly decreased the ratio of adenosine monophosphate (AMP) to adenosine triphosphate (ATP) in the liver, but increased ATP content and adenylate energy charge (AEC) in a quadratic and linear manner, respectively (P < 0.05). Increasing dietary AKG supplemental levels produced linear positive responses in ATP content and AEC, and negative responses in AMP concentration, the ratio of AMP to ATP and total adenine nucleotide in the ileal mucosa (P < 0.05). All levels of dietary AKG reduced the production of jejunal hydrogen peroxide and hepatic malondialdehyde (P < 0.05). Hepatic and ileal messenger RNA expression of AMP kinase α‐1 and hypoxia‐inducible factor‐1α were linearly up‐regulated as dietary AKG supplemental levels increased (P < 0.05). In conclusion, dietary AKG supplementation linearly or quadratically enhanced hepatic and intestinal energy storage and anti‐oxidative capacity of Cherry Valley ducks.     

Supplemental magnolol improves the antioxidant capacity and intestinal health of broiler chickens

Magnolol is a multifunctional polyphenol rich in Magnolia officinalis. The objective of this study was to investigate the effects of magnolol on growth performance, carcass traits, antioxidant capacity, and gut health of broiler chickens. A total of 240 1-day-old broilers were randomly allocated into five dietary treatments: control (Ctrl); control diet supplemented with 100, 200, or 300 mg/kg of magnolol (M100, M200, and M300); and control diet supplemented with 200 mg/kg of bacitracin zinc (PC). The results showed that magnolol linearly decreased the feed conversion ratio between d 0 and d 14, linearly decreased the amount of malondialdehyde and increased the activity of total superoxide dismutase (T-SOD) in both serum and ileal mucosa on d 42 with increasing magnolol levels (p < 0.05). Moreover, the ileal villus height, the ileal villus height to crypt depth ratio, and the jejunal gene expressions of SOD1, glutathione peroxidase, and Claudin1 were linearly up-regulated with increasing magnolol levels (p < 0.05). The supplementation of magnolol had no effect on carcass traits or cecal short chain fatty acids (p > 0.05). The results indicated that magnolol could be applied in the diet of broiler chickens to benefit their antioxidant capacity and intestinal health.     

Dietary lysine requirement for 7–16 kg pigs fed wheat–corn–soybean meal‐based diets

Two experiments were conducted to determine the lysine requirement of weaned pigs [Duroc × (Yorkshire × Landrace)] with an average initial BW of 7 kg and fed wheat–corn–soybean meal‐based diets. The experiments were conducted for 21 days during which piglets had free access to diets and water. Average daily gain (ADG), average daily feed intake (ADFI) and gain to feed ratio (G:F) were determined on day 7, 14 and 21. Blood samples were collected on day 0 and 14 to determine plasma urea nitrogen (PUN) concentration. In experiment 1, 96 weaned pigs were housed four per pen and allocated to four dietary treatments with six replicates per treatment. The diets contained 0.99%, 1.23%, 1.51% and 1.81% standardized ileal digestible (SID) lysine, respectively, corrected analysed values. The rest of the AA were provided to meet the ideal AA ratio for protein accretion. Increasing dietary lysine content linearly increased (p < 0.05) ADG and G:F. In experiment 2, 90 piglets were housed three per pen and allocated to five dietary treatments with six replicates per treatment. The five diets contained 1.03%, 1.25%, 1.31%, 1.36% and 1.51% SID lysine, respectively, corrected analysed values. Increasing dietary lysine content linearly increased (p < 0.05) G:F, linearly decreased (p < 0.05) day‐14 PUN and quadratically (p < 0.05) increased ADG and ADFI. The ADG data from experiment 2 were subjected to linear and quadratic broken‐lines regression analyses, and the SID lysine requirement was determined to be 1.29% and 1.34% respectively. On average, optimal dietary SID lysine content for optimal growth of 7–16 kg weaned piglets fed wheat–corn–SBM‐based diets was estimated to be 1.32%; at this level, the ADG and ADFI were 444 and 560 g, respectively, thus representing an SID lysine requirement, expressed on daily intake basis as, 7.4 g/day or 16.76 mg/g gain.     

Endogenous fat losses and true and apparent fat digestibility in adult and growing dogs fed diets containing poultry offal fat

The objective of this study was to evaluate the coefficient of total tract apparent digestibility (CTTAD) of dietary nutrients, endogenous fat loss (EFL), dietary metabolizable energy (ME) content, coefficient of true digestibility (CTD) of fat and faecal parameters of dogs. A total of 16 puppies and 8 adult dogs were distributed according to a double Latin square experimental design. A basal diet was formulated, to which increasing levels (60, 120 and 180 g/kg) of poultry offal fat oil were added. EFL was estimated using hyperbolic and linear regression as a function of LW/day and dry matter (DM) intake, respectively, and the CTD of fat was calculated. The CTTAD of acid-hydrolysis ether extract (AHEE) and ME content increased as dietary poultry offal fat level increased both in adult dogs and in puppies (p < .05). The CTTAD of DM and crude protein were higher in adult dogs than in puppies. EFL was estimated by hyperbolic regression as y = 98.1094 − 13.6202/x and y = 99.1280 − 26.1366/x, where y = CTTAD of AHEE (%) and x = AHEE intake/kg BW, for adult dogs and puppies, respectively, which yielded EFL values of 138 and 262 mg AHEE per kg BW per day for adult dogs and puppies respectively. The EFL estimated by linear regression was 7.89 g and 8.97 g/kg DM intake for adult dogs and puppies respectively. The CTD estimated by both methodologies was higher in puppies than in adults (p < .05). Lower faecal DM and score, and higher ammonia production were obtained in puppies than adult dogs (p < .05). The results indicate good fat utilization and that fat digestibility is underestimated, as the CTTAD of AHEE does not take into account EFL, particularly at low-fat inclusion levels and in growing dogs, which have greater EFL than adult dogs.     

Effect of dietary Moringa oleifera leaves on the performance,ileal microbiota and antioxidative status of broiler chickens

In this study, we investigated the effect of Moringa oleifera leaves (MOL) supplements on the performance, ileal microbiota carcass traits and biochemical and antioxidant parameters of broiler chickens. MOL was added to starter, grower and finisher diets at four levels (0%, 0.5%, 1.0% and 5.0%). A total of 320 one-day-old mixed-sex Cobb-500 broiler chicks were divided equally into four treatment groups, with 5 replicates of 16 chicks each until 42 days of age. Compared to the control group, chicks fed 0.5% and 1% MOL exhibited a higher final body weight (FBW), greater weight gain (BWG), and better average daily gain (ADG). Feed intake (FI) gradually decreased as the inclusion rate of MOL in the broilers' diet increased to 5%. The best feed conversion ratio (FCR), protein efficiency ratio (PER) and performance index (PI) were observed in broilers that were fed the MOL diet. The percentage of abdominal fat in broilers decreased significantly in response to dietary supplementation with MOL. The haematological profile in the MOL group revealed a lower WBC count and lymphocyte percentage but higher heterophil and H/L ratio without affecting haemoglobin and RBC count. The inclusion of MOL increased total serum protein, Ca and P levels but decreased glucose, cholesterol, triglycerides, AST and ALT concentrations. Moreover, dietary MOL increased the activities of GSH, CAT and SOD, GPx and GST while decreasing the TBARS level. The pH value decreased in the ileum of broilers fed the 1% and 5% MOL diet compared to the other treatments. Decreased ileal counts of E. coli, Salmonella and Staphylococcus spp. were observed whereas the total ileal Lactobacillus spp. count increased in broilers fed the MOL diet. In conclusion, the MOL supplement can enhance growth performance and antioxidant status, alter ileal microbiota and protect against enteropathogens with no deleterious effects on the broiler chickens.     

Nitrogen balance and ileal amino acid digestibility in growing pigs fed diets reduced in protein concentration

Two studies were conducted to assess the effect of dietary protein reduction on N utilization, N excretion, and AA digestibility in growing pigs. The objective was to determine whether pigs fed diets with a reduced CP concentration could maintain the same N retention as pigs fed an adequate diet. The second objective was to test whether reducing dietary CP concentration decreases AA digestibility. In each study, six barrows were allotted to one of six dietary treatments in a Latin square design. Treatments consisted of four corn-soybean meal-based diets containing 15, 12, 9, and 6% CP, a casein-based diet containing 15% CP, and a protein-free diet. Crystalline AA were included in the 12, 9, and 6% CP diets. The indispensable:dispensable AA ratio was maintained at 45:55 with the addition of L-glutamic acid to the 9 and 6% CP diets. The casein-based and protein-free diets were used to determine endogenous total tract N and ileal AA losses. In the first study, total N losses and N absorbed decreased linearly (P < 0.001) as dietary CP concentration decreased from 15 to 6%. Both a linear (P < 0.001) and a quadratic (P < 0.05) decrease in N retention were found with decreasing dietary CP concentration. Nitrogen retained as a percentage of intake and absorbed increased (P < 0.001) as dietary CP concentration was reduced from 15 to 6%. In the second study, six barrows were surgically fitted with a T-cannula at the terminal ileum to determine ileal AA digestibility. For all dispensable and most indispensable AA, apparent and standardized ileal digestibility increased linearly (P 0.01, and for arginine, P < 0.05) as dietary CP concentration decreased. These results indicate that dietary CP concentration can be decreased from 15 to 12% with crystalline AA supplementation to meet an ideal AA profile without adversely affecting N retention, and that decreasing dietary CP concentration from 15 to 6% increases both dispensable and indispensable AA ileal digestibility.